Tbi off idle stumble

x2 The sub is a 350 TBI, it idles rough, almost like it's running out of fuel and coming off lights it will stall out. Then when I let it sit for a day it drives great and only idles rough. New parts: Fuel pump, fuel filter, EGR valve, radiator, water pump, temp sensor, starter, fuel relay, distributor, cap, rotor, wires, plugs.A number of the early TBI vehicles I've driven have a fairly aggressive throttle tip-in. Sometimes, if you can modulate the throttle with a velvet slipper, you can actually get the engine to stumble a little between on and off idle instead of lurch. But it's never a particularly smooth transition.Engine stumbles off-idle after warmed up. Jump to Latest Follow 1 - 5 of 5 Posts. mnunn · Registered. Joined Jun 26, 2005 · 1,200 Posts . Discussion Starter · #1 · Mar 16, 2006. Here's my TPI question: ...Search: Holley carb part throttle stumble. About part throttle Holley stumble carbThe first few days a stumble off stop, that seems to have cleared a bit, but I do notice it randomly still. It feels like the car is loading up on fuel then clears up with acceleration. Oddly, when first started, the idle starts at 1000RPM, but will climb after warming up or after being driven , or when in Park/Neutral.Symptom is an off-idle stumble (most noticed from a standing start) and low speed cruise surging (25-40mph). I have replaced: cap, rotor, ign. modual, plug wires, plugs, dist. cap harness, throttle possition sensor and harness plug, catlytic converter, exhaust resonator, and various and assundry other minor items.He said running certain adapter plates could cause anomalies like that, along with erradic idle and off idle stumble. Having the 1" of open plenum before it goes into a dual plane manifold (we are all running Edelbrock Performers) causes a swirling of air/fuel and uneven flow to all the plenums.This eliminates the lean stumble even on 454's. Flip side is the O2 sensor cooling off can go back into open loop and be too rich. During warm up at idle you can be both rich or lean depending on the temperature, fuel, and part of the program running.I swapped the 1 and 4 plug wires at the coil, and then discovered that my car ran lousy with a marked hesitation and stumble off idle. So if you are searching the forums because your car hestitates off idle check the plug wire order. It most definitely matters. This is covered in many other forum posts.On steep hills our 1406 will run out of fuel, there is no black smoke at all. We have to back it down and let the bowls fill back up and then go up real fast. At cruse it is lean off the scale of the gage. I adjisted the idle mixture screws to richen it up at idle per the reading on the gage as a lean condition will caulse a stumble per the book.TBI being a MAP sensor based system will see the leak just like opening the throttle blades and will feed the leak and then you have a high idle. Finding the leak can be tricky as it can be the intake gasket on the bottom side if you are using a Chinese junk carb intake or you weren't real careful putting the intake on.Off Idle Stumbles Was curious a good place to start with some off idle stumble when the car gets some heat into it. It seems like leaving a stoplight over 170° of oil or water temp it wants to stumble & hesitate. It's a 9.5:1 1400 RWHP E85 TT SBC, everywhere over 1800 RPM seems to be OK. On the throttle or tip-in below that isn't happy.Apr 04, 2011 · The 02 reading starts out at idle a little biased lean, but switching, then as soon as into accelerator truck stays lean until open loop. 58-65 mv is normal when leans out. Fuel gage never wavered at 12-13 psi. MAP around 2.9v when PW 2.8MS when truck seemed to be falling a little flat under brake torque. If you suspect that the EGR valve is behind your engine's rough idle condition, this tutorial will help you to troubleshoot it with 2 simple tests. NOTE: This tutorial covers the EGR valve of the 1987-1995 throttle body fuel injection (TBI) system of the 4.3L, 5.0L, and 5.7L GM engines.May 22, 2019 · Of course assuming at this point does not get answers. as to the other truck getting better fuel mileage it was a 1600 Loadstar, with a 345 set up with the same pro jection system, and a 4 speed, with two speed rear, and in high, ratio of 5.8, the bus is 5.14 in high on the rear. The 1600 was grossing 26,000 lbs, and the bus is 18,000lbs normal ... 2. Engine won't idle smoothly, idles too slowly, or stalls. If you start to experience engine misfires, stalling, or rough idling when the car is stopped, it can also be a warning sign of a failing TPS. You don't want to wait to get this checked out! If the idling appears off, it means the computer is unable to identify the fully shut throttle.Welding it fixed that problem, but now I have the 1000rpm idle problem with my 650DP. I got it used, put a renew kit in it, and got it working 95% right, but never could clear up an off-idle stumble. After messing with it last weekend, it won't idle below 1000(EFI smog cam capable of 600rpm idle).Fuel pressure for the TBI ('82-'84) is 9-13 psi, whereas fuel pressure for the TPI (LT1) is an operating rating of 50 PSI and 24 GPH. I'm not surprised you blew the TBI out. Rough idle is probably TBI related, especially since you over-pressured the TBI. You may want to "rebuild" the TBI's.There should be no EGR flow at idle, only under load. That said, since the issue is under load, that would normally indicate a problem with the ignition system since it will likely fail under load but it sounds like you've covered most of the parts on the ignition system. This leaves fuel delivery. The old TBI systems could be tricky.There's a stumble at idle, but there really isn't any indication that the idle is too low. Everywhere I've read says that the idle is supposed to be around 800rpm and that seems to be where it's at. It's hard to tell because of how the stock tach is labeled. It seems it stumbles moreso when coming to a stop sign off a higher rpmIt's easier to show the symptoms that to explain them some times...Aug 09, 2012 · Every once in a while I'll go to take off when the light turns green and the bike will stumble just off idle and die. It usually happens while I'm slowly releasing the clutch and simultaniously giving the bike throttle. It's like it hits a weird spot in the fueling and the bike can't take any load while idling so it just stalls when the ... Along with the erratic idle, the engine has absolutely zero power. It stumbles as if it's missing a couple of cylinders when you accelerate. It has a hard time with ANY load (even the A/C compressor). I checked all of the wires and they are all good and tight on the plugs. Also made sure that they are going to the right cylinders.Number one is for Idle AFR, which can range from 13.4 to 14.7 on average, depending on the engine. Adjusting this setting will help idle quality and takeoff from an idle. 1100, 3000, 6000 at 45kpa cruise are your cruising AFR ratios, and these can vary from 13.8 to 14.7 on average depending on the engine's needs and your desired fuel economy.Short summary: Stumble off idle under hard acceleration. -rebuilt carb. -manifold distributor advance set at 8 degrees BTDC. -idle mixture screws set to the rich side at 2-1/2 turns out. -replaced power valve twice. -replaced accelerator pump twice. -very slight vacuum leak on driver side of throttle shaft.1 Answer Your problem is probably going to be the egr valve. in is mounted on your intake next to your coil behind the tbi unit. it looks a little like a pancake flat adn round and it has one vacuum line going to it. pull that vacuum line from the valve and see if it still stumbles.When driving it shudders erratically at idle when in gear (ie: at a stoplight). 350 Tbi Stumbles At Idle from 250hp to 260hp the fuel pressure should be bumped up to 13-14psi on stock 350 truck injectors which will change their flow rating to 60lb/hr. Jump to Latest Follow 1 - 20 of 36 Posts.So I have a 74 with Howell TBI the PO installed. I have a miss or a stumble best way I know to describe it. I have new coil, spark plugs, ignition wires,points, and O2 sensor all with less than 50 miles or 3 hours run time. I had a bad alternator and upgrade to a 3g truck seemed to wake up...I had a similiar problem when running my edelbrock 500 cfm on my Clifford intake on my 250. 2001 Carburetors - Edelbrock carb stumbles off idle - I just build me a complete motor with the edelbrock performer RPM package, cam, carb, [Archive] installed edelbrock 1406, dies under load General FSJ Tech. 1. 7L TBI intermittently stumbles/stalls at ... I swapped the 1 and 4 plug wires at the coil, and then discovered that my car ran lousy with a marked hesitation and stumble off idle. So if you are searching the forums because your car hestitates off idle check the plug wire order. It most definitely matters. This is covered in many other forum posts.1995 K1500 350 TBI Stumble was created by 93Rubie. Have a odd one and looking for any ideas. Has a stumble/misfire only at hot idle. More noticeable in gear. Fuel trims are about 128/134 so good. 02 sensor cycling rich and lean. Spark is solid from coil on scope and cylinder drop test. Each cylinder drops more or less equal rpm at idle.The problem is the engine will start and idle, but won't run anything past a fast idle before it stumbles and dies. We crank it over and eventually it starts but runs through the same problem. The engine is a basically stock 454 with a Performer RPM dual plane intake, a 750 cfm Holley, and headers.So it was the coil then. Thats good to know cuz my truck just started doing the same thing (92 GMC). Idles fine, drives on fwy etc fine, but stumbles when taking off from a stop, then its fine after that. Just did the cap, rotor, wires, and plugs, but it didn't fix it. Gonna do the coil tonight.-DaveEngine stumbles off-idle after warmed up. Jump to Latest Follow 1 - 5 of 5 Posts. mnunn · Registered. Joined Jun 26, 2005 · 1,200 Posts . Discussion Starter · #1 · Mar 16, 2006. Here's my TPI question: ...Idle speed is the speed at which the crankshaft rotates when the throttle plate or valve is closed or at rest. On modern vehicles, the computer controls idle speed, although a bad or failing sensor or mechanical malfunction can upset it. On older car models, though, adjusting idle speed is part of the tune-up procedure. I have a 92 350 TBI she is hard starting when its cold. I have to turn it over several times in order to get it to start than I have to feather the gas alot in order to keep it running after a few minutes it idles on its own really low idle. Than it smooths out as truck warms up and runs like a champ and when its warm truck starts right up.The infamous GL1800 stumble caught on video. This is a video I took today of the infamous GL1800 stumble. Please let me know if this is what others are experiencing as well. Some background. The bike had been ridden a short distance, then parked outside for about 30 minutes. Ambient temperature outside was ~75 degrees.All groups and messages ... ...Tim Rif. 03-04-2006, 12:45 PM. I just installed a 454 TBI long block in my '89 Silverado. When I first fired it up it ran great. I adjusted the IAC (which I shouldn't have) to get the engine up to 1500 rpm's for about 15 minutes. I backed the IAC off after 15 mins (back to around 1000 rpm's) and it ran pretty rough (didn't want to stay running).Search: 350 Tbi Stumbles At Idle. About Tbi Idle At 350 StumblesI had a similiar problem when running my edelbrock 500 cfm on my Clifford intake on my 250. 2001 Carburetors - Edelbrock carb stumbles off idle - I just build me a complete motor with the edelbrock performer RPM package, cam, carb, [Archive] installed edelbrock 1406, dies under load General FSJ Tech. 1. 7L TBI intermittently stumbles/stalls at ... Running Issues with Howell TBI. A couple of months ago, I installed the Howell TBI into my CJ7. I have the 258. It is the JP1 kit, 50 state smog legal. After install, all was great. Ran excellent. Not a single issue. After buzzing around town for a few weeks, I (and a few others from MJR) went to Millers. One the downhill portion of the trails ... The idle air control valve is responsible for managing the engine idle speed. The valve is a major management component of the engine which will either decrease or increase the number of revolutions per minute, depending on what the current operating conditions call for.Along with the erratic idle, the engine has absolutely zero power. It stumbles as if it's missing a couple of cylinders when you accelerate. It has a hard time with ANY load (even the A/C compressor). I checked all of the wires and they are all good and tight on the plugs. Also made sure that they are going to the right cylinders.Basicly, I have limited power, off idle stumble, and a slight pop out of the exhaust when shifting. It takes alot to get the rpms up and seems to lose power about 4500 rpm. When idling, a distinctive stumble is heard and throttle response is not that great. Also, if I adjust mixture needles for optimum vacuum, the idle shoots up and I can't get ...1989 Dodge D150 318ci TBI 2wd 1/2 ton Automatic Symptoms: Idle raises and lowers, after warming up. Engine stalls when you come to a stop, after the engine warms up. Things I have done: Checked for injector operation. Replaced fuel filter. Checked fuel pressure. Replaced cap, rotor, plugs, and...May 12, 2015 · Throttle response is great with no hint of off idle hesitation or full throttle stumble. Cons: The system will run returnless but it has a tendency to vapor lock in this configuration as ambient air temperatures rise in the summer months. 5.7 V8 TBI stumbles. Maintenance/Repairs. Jonfly673. July 4, 2016, ... On the OBD connecter while the key is off install a paper clip between the 2 slots on the bottom row on the right corner and then turn on the ignition but don't start the engine. In a few seconds the CEL light will blink 2 digit codes. ... On my 92 Corolla during a tune-up ...I started off by dropping the 1.6L long block into my Samurai, then I bolted up the Samurai's intake manifold/TBI. It started just fine, but ran rough at idle, with occasional misses. I double checked cam timing, ignition timing, fuel pressure, etc. I spent about an hour driving it around. I was a little bit disappointed with its performance.This can cause a very uneven idle, which can jump up and down, and the engine may also shut off on idle. Re: 1995 TBI 350 with 214k stumbles a little at idle, otherwise runs great After further reading, I'm starting to lean on the IAC being the problem. Also stumbles and occasionally will stall when first started in the morning.Your off idle stumble is most likely the accelerator pump or the adjustment of it and no amount of tuning or timing is going to fix that so try to put that out of your mind for now. Just get it to run, then rebuild the carb. Bill _____ '65 Buick Skylark, 406 sbc, 10.07 comp, ported Trick Flow 195 heads, RPM Air gap, Holley 3310, Straub HR .547 ...It is off idle FLODDING - smoke in all. Will only clean out when past that throttle spot. The tps checked at .6 idle to 4.36 at wide. The MAP checked at 4.6 not run and 1.01 when idle. Both are in spec with my Hayes manual. I can recheck the tps to check for the .01 increase right at the Fat spot - but? Thanks Again, Craig1995 chevy silverado wont idle and stalls when stopping. i have a 1995 silverado 5.7liter 350 engine, i replaced the motor,the other motor had 225,000plus miles. after replacing the motor it will not idle,and stalls out when stopping, also noticed that the motor surges, when applying the throttle it will rev up,but it will try to die off unless ...The problem is the engine will start and idle, but won't run anything past a fast idle before it stumbles and dies. We crank it over and eventually it starts but runs through the same problem. The engine is a basically stock 454 with a Performer RPM dual plane intake, a 750 cfm Holley, and headers.On an MPFI "dry throttle" engine, a very high idle usually fingers an extreme vacuum leak. But TBI is more akin to the carburetors of days of yore, where a vacuum leak is more likely to make the car stumble or stall. This high an idle must mean something else. A really goofed up idle air control solenoid, or something wrong with the injector ...Throttle response is great with no hint of off idle hesitation or full throttle stumble. Cons: The system will run returnless but it has a tendency to vapor lock in this configuration as ambient air temperatures rise in the summer months.Location Colorado Jun 19, 2006 #1 TBI is surging with steady part throttle in open loop when cold. Especially when it's been driven - shut down for an hour - and restarted. The surge is like a whup-whup-whup-whup until I add throttle and rev it out. It goes away after I drive it for a minute or it warms up to closed loop.The 90 degree elbow in the PCV Valve hose at the base of the throttle body to the PCV valve is common to either fall off or have a hole in it. Most of the time the engine will idle at a higher RPM a suction sound can be heard. The hose is available in the "HELP" section at any Auto Parts store. I think the part is a DORMAN# 46001.Throttle response is great with no hint of off idle hesitation or full throttle stumble. Cons: The system will run returnless but it has a tendency to vapor lock in this configuration as ambient air temperatures rise in the summer months.May 22, 2019 · Of course assuming at this point does not get answers. as to the other truck getting better fuel mileage it was a 1600 Loadstar, with a 345 set up with the same pro jection system, and a 4 speed, with two speed rear, and in high, ratio of 5.8, the bus is 5.14 in high on the rear. The 1600 was grossing 26,000 lbs, and the bus is 18,000lbs normal ... Eleonar1. I have a 1998 5.7L TBI Mercruiser Alpha 1 gen 2, closed cooling, that's having problems. I recently installed a new long block along with manifolds & risers as the original motor blew with about 870hrs on it. The issue I am having is it will only idle for about 15-20 seconds, after this the IAC opens too much, there is a loud hissing ...Lifted_Bowtie. Hey guys, I finally got my 350 up and running, she purrs like a kitten and is stronger than EVER! I have 70 to 75 pounds oil pressure cold and 40 - 45 warm and 70 pounds when i get on the pedal! Although im having trouble with the tbi i assume. the engine will stall when coming to stop at a stop light, but it stalls and shuts off ...Now it has a erratic idle. When cold the engine idles around 1400 rpm, when giving it gas the engine seems to stumble then takes off, then stumbles and goes. It's noticeable when driving. Once the motor is warmed up the idle is around 500 rpm but it acts like it misses, then idles up to 700 rpm. This when in gear.Fuel pressure is rock solid 14.2 engine off, 16.5 engine running with vacuum supplied, doesn't change more than .2psi regardless of load, anything from idle to 4k under WOT. Spray pattern is decent, not great, not terrible though, no leaks with the key off, system holds pressure. Vacuum is 20" and smooth.Hi everyone Have a problem with my Vortec 5.7 -4l60e. It has started to "stumble" Or "Hacks" (mike to violently) sometimes when driving. It almost feels Like when you hit the rev. limiter and it just shuts of the ignition. but it feels when driving like it's in the gearbox. When accelerating...Idle speed is not controlled by an adjustment screw on the throttle linkage, but by an idle air control bypass valve operated by a solenoid or electric motor and the controller. On most of the bolt-on TBI systems, the throttle is still mechanical and connects the same as a carburetor with a cable or linkage and return spring.1989 Dodge D150 318ci TBI 2wd 1/2 ton Automatic Symptoms: Idle raises and lowers, after warming up. Engine stalls when you come to a stop, after the engine warms up. Things I have done: Checked for injector operation. Replaced fuel filter. Checked fuel pressure. Replaced cap, rotor, plugs, and...May 22, 2019 · Of course assuming at this point does not get answers. as to the other truck getting better fuel mileage it was a 1600 Loadstar, with a 345 set up with the same pro jection system, and a 4 speed, with two speed rear, and in high, ratio of 5.8, the bus is 5.14 in high on the rear. The 1600 was grossing 26,000 lbs, and the bus is 18,000lbs normal ... How to reset the baseline idle speed in a GM TBI? Turn the screw to adjust the idle speed to 650 RPM +/- 50 RPM. Turn off the engine and disconnect the negative battery terminal from the battery using a wrench. Reconnect the IAC valve. Reinstall the air cleaner and remove the paper clip from the ALDL connector. Cliff-notes below. 1995 TBI 5.7L, about 235,000 miles on original motor. A few weeks ago on the way home from work, my 95 began stumbling/misfiring under load. As long as I stayed under about 1/4 throttle, it was okay. Getting closer to home, it began backfiring through the exhaust. Didn't...Similar situation if I don't have throttle in right place for about 10 sec in winter (not my daily, so haven't bothered chasing down high idle with IAC connected) Daily_Project Status: It's been an on/ off affair for years. 1994 Chev astro awd 4.3l 700R.The idle issue is mostly resolved (still has a slight vibration but that could just be motor mounts). However a new issue has arisen: I have a bog/stumble when accelerating, most noticeable off idle but also happens accelerating out of about 20-30mph.My truck bogs down (and tries to die) when I give it gas to accelerate off of a stop. There is often a backfire or two when this happens. Pumping the gas does not help. I basically have to crawl through any intersection until it picks up a bit of speed from idle. The truck idles smoothly, and it runs fine once it's above about 5-10mph or so. If moving at a steady speed, and I give the truck ...A number of the early TBI vehicles I've driven have a fairly aggressive throttle tip-in. Sometimes, if you can modulate the throttle with a velvet slipper, you can actually get the engine to stumble a little between on and off idle instead of lurch. But it's never a particularly smooth transition.5.7 V8 TBI stumbles. Maintenance/Repairs. Jonfly673. July 4, 2016, ... On the OBD connecter while the key is off install a paper clip between the 2 slots on the bottom row on the right corner and then turn on the ignition but don't start the engine. In a few seconds the CEL light will blink 2 digit codes. ... On my 92 Corolla during a tune-up ...It is off idle FLODDING - smoke in all. Will only clean out when past that throttle spot. The tps checked at .6 idle to 4.36 at wide. The MAP checked at 4.6 not run and 1.01 when idle. Both are in spec with my Hayes manual. I can recheck the tps to check for the .01 increase right at the Fat spot - but? Thanks Again, CraigI can hear it trying to stumble, but in high gear it doesn't jerk the car so much and when I back off, I can stop right at the limit of the stumble. Key Words: Tune up, tune-up, rough poor idle, low power, power loss, mpg loss, pop, stumble, jerk, jerky, sputtering, hesitation, backfire back fireFollow. Asked by coyboy350 Jan 05, 2015 at 10:20 PM about the 1994 Chevrolet C/K 1500 Silverado Extended Cab 4WD. Question type: General. 94 5.7 tbI I have replaced every sensor on. motor had igniton timing redone. The truck. has full power while driving. Just low idle at. 400rpm and has a slight stutter.Nov 25, 2002 · Most of your off idle problems come from these screws regardless of the state of the main jets and needle positions. But if you still be a stumble revving it to 5 grand and taking off then there's LOTS of issues to deal with. At 5 K you're well up into the needle and main's range. I installed the Howel TBI on my '85 CJ7 with the 258. I am about to see if it smogs, I have been driving it to get the computer settled in but I am concerned about a stumble coming off idle. It idles at 750 and runs well at the upper RPM range but starting off in first it'll stumble and feels...RE: 3.9 TBI DUMPING fuel, sputtering IP: Logged Message: code 41* Alternator field control circuit open or shorted Maybe it's a charging problem such that the voltage reference in the MAP sensor is off. Have you checked your charging system? Should be 14-14.5 volts at idle, 12.4 or so volts off with battery fully charged. Caver Dave Dodge DakotaEngine stumbles off-idle after warmed up. Jump to Latest Follow 1 - 5 of 5 Posts. mnunn · Registered. Joined Jun 26, 2005 · 1,200 Posts . Discussion Starter · #1 · Mar 16, 2006. Here's my TPI question: ...Hi folks, When the truck is stopped and in gear, and I put my foot lightly on the gas, I'll get a stumble or bog - like the timing suddenly retards - and then I'll take off quick, as soon as the engine is out of that little area around 1000-1200 RPM. If the engine is really cold, and I don't give the idle time to settle out after starting, that bog will turn into a miss or a CLUNK the first time.TBI Assembly 900 CFM 85 lb/hr Complete 1 534-173 2 Avenger EFI ECU and Handheld 1 554-116 3 Main Power Harness 1 558-308 4 Avenger EFI TBI Wiring Harness 1 558-100 5 Inline Pump 1 N/A 6 Metal Fuel Filter 1 562-1 7 Fuel Filter (WIX 33033) 1 N/A 8 Fuel Filter Clamp 1 N/A 9 Fuel Pump Block-Off Plate & Gasket 1 12-813You might want to check the EGR valve and for vacuum leaks. check the air idle solenoid on the TBI. sometimes you can remove them and clean the carbon from them using gum cutter. if this doesnt work, check the knock sensor. if this does not work you might have a internal vacuum leak. ajs79lincoln 12-19-2004, 10:05 PMAbout Tbi 350 Idle At Stumbles . No power loss or hesitation. This data is wrong. but fires up almost instantly after warmed up, However if I put it in gear the truck will idle at about 600ish but will consistly drop to 500 and sometimes hit the 450rpm mark but pick back up.Mar 22, 2013 · How can you tell if an off-idle stumble is caused by a lean or a rich condition? A carb running rich, as well as a carb running lean, can cause an off-idle stumble or hesitation upon acceleration. To narrow it down, tap the roll pin out of the accelerator pump lever by using a small pin punch or a small finish nail. I actually use a small ... Jul 30, 2009 · Everything I've ever encountered with a hesitation off idle came with a rough idle also. If your not having the rough idle, then I believe your problem might be the injectors. Just taking a guess, I'd say the idle doesn't need much fuel but taking off from idle fuel needs to increase, if it doesn't then a hesitation occurs, but the same for ... Subject: Idle? Date: Mon, 13 Apr 1998 10:54:39 +1200. Yep, its FIXED! Thanks Steve, for that draft of the dissertation on how to fix idle/stumble. It turned out to be the throttle sensor connector, managed to remove some almost chrome flake looking stuff off the make connectors! Tightened it all back up, and threw it on.used throughout GM up until about 1995. <c>Do not get one off a super or turbo charged engine, or from pre TBI cars such as the 307 Olds engine you will be looking for to find a suitable distributor. They are manifold differential pressure sensors as opposed to absolute pressure sensors. <c>Output is a bit Idle speed is not controlled by an adjustment screw on the throttle linkage, but by an idle air control bypass valve operated by a solenoid or electric motor and the controller. On most of the bolt-on TBI systems, the throttle is still mechanical and connects the same as a carburetor with a cable or linkage and return spring.Won't idle The truck will not idle and is low on power. When it tries to idle it smells very rich. If driving at light throttle it coughs and stumbles. I have tried everything I know to fix it. Replaced the distributor, map, o2, tps,plugs, rotor, cap. wires.The idle is the same cold or warm and I don't have to slam the peddle several times to get off of high idle and drop the choke. I have been doing a lot of start and stop testing and there is no more dieseling. The little flashing light says the motor is running closed loop which says it is in control. ... This is the start of a Howell TBI ...Mar 22, 2013 · How can you tell if an off-idle stumble is caused by a lean or a rich condition? A carb running rich, as well as a carb running lean, can cause an off-idle stumble or hesitation upon acceleration. To narrow it down, tap the roll pin out of the accelerator pump lever by using a small pin punch or a small finish nail. I actually use a small ... Lifted_Bowtie. Hey guys, I finally got my 350 up and running, she purrs like a kitten and is stronger than EVER! I have 70 to 75 pounds oil pressure cold and 40 - 45 warm and 70 pounds when i get on the pedal! Although im having trouble with the tbi i assume. the engine will stall when coming to stop at a stop light, but it stalls and shuts off ...Makes idle in park around 1700 rpms. In 4low with idle adjusted up, truck still stalls when dropped in gear, unless throttle finesse is applied. 2) Still runs rich at idle according to checking the plugs after being brought up to temp. The only good thing is that the truck runs pretty darn good once warmed up, off idle. roasting 42's.Follow. Asked by coyboy350 Jan 05, 2015 at 10:20 PM about the 1994 Chevrolet C/K 1500 Silverado Extended Cab 4WD. Question type: General. 94 5.7 tbI I have replaced every sensor on. motor had igniton timing redone. The truck. has full power while driving. Just low idle at. 400rpm and has a slight stutter.This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project to make the world's books dis Apr 04, 2011 · The 02 reading starts out at idle a little biased lean, but switching, then as soon as into accelerator truck stays lean until open loop. 58-65 mv is normal when leans out. Fuel gage never wavered at 12-13 psi. MAP around 2.9v when PW 2.8MS when truck seemed to be falling a little flat under brake torque. I started off by dropping the 1.6L long block into my Samurai, then I bolted up the Samurai's intake manifold/TBI. It started just fine, but ran rough at idle, with occasional misses. I double checked cam timing, ignition timing, fuel pressure, etc. I spent about an hour driving it around. I was a little bit disappointed with its performance.Apr 30, 2014 · Concord,NC. May 1, 2014. #5. The engine is originally from a 1993 Suburban, I have some specs on the engine, the block has been bored .040 over,heads resurfaced .007, it has flat top pistons (h-345acp-040), a (cs-1014-r) camshaft, a tbi spacer and injector spacer and a lower temp thermostat. I also installed a complete accel ignition system ... I installed the Howel TBI on my '85 CJ7 with the 258. I am about to see if it smogs, I have been driving it to get the computer settled in but I am concerned about a stumble coming off idle. It idles at 750 and runs well at the upper RPM range but starting off in first it'll stumble and feels...Apr 04, 2011 · The 02 reading starts out at idle a little biased lean, but switching, then as soon as into accelerator truck stays lean until open loop. 58-65 mv is normal when leans out. Fuel gage never wavered at 12-13 psi. MAP around 2.9v when PW 2.8MS when truck seemed to be falling a little flat under brake torque. About Tbi 350 Idle At Stumbles . No power loss or hesitation. This data is wrong. but fires up almost instantly after warmed up, However if I put it in gear the truck will idle at about 600ish but will consistly drop to 500 and sometimes hit the 450rpm mark but pick back up.The off idle throttle response is kind of rough, as I go to let the clutch out from a stop it will stumble or sputter a bit before it clears itself and will run perfectly smooth above 1200rpms or so. It has a comp 270ahr with the stock tuning right now, I removed the hypertech tuning before I ran it for the first time but I will be doing a ...Jun 20, 2006 · Location Colorado Jun 19, 2006 #1 TBI is surging with steady part throttle in open loop when cold. Especially when it's been driven - shut down for an hour - and restarted. The surge is like a whup-whup-whup-whup until I add throttle and rev it out. It goes away after I drive it for a minute or it warms up to closed loop. • erratic idle, drops from 1,500 rpm to low hundreds in a few seconds, when the idle is stable it is at 1,100-1,350rpm although the unit is set to 950 rpm • car stalls when coming to a stop unless kept in gear • backfiring on deceleration The mechanic who is troubleshooting the system can't figure it out and MSDs tech line has been no help.1. 4.3L Vortec ICV and TPS Failure. The idle control valve ("ICV") and throttle position sensors ("TPS") are prone to failure on all 4.3 engines, which can result in poor idling, engine stalling, bad acceleration, and other low-rpm running problems. The idle control valve sits on the throttle body and is responsible for adjusting the ...changing out the seems like forgotten idle air control on a chevy tbi. changing out the seems like forgotten idle air control on a chevy tbi.Lifted_Bowtie. Hey guys, I finally got my 350 up and running, she purrs like a kitten and is stronger than EVER! I have 70 to 75 pounds oil pressure cold and 40 - 45 warm and 70 pounds when i get on the pedal! Although im having trouble with the tbi i assume. the engine will stall when coming to stop at a stop light, but it stalls and shuts off ...Idle speed is not controlled by an adjustment screw on the throttle linkage, but by an idle air control bypass valve operated by a solenoid or electric motor and the controller. On most of the bolt-on TBI systems, the throttle is still mechanical and connects the same as a carburetor with a cable or linkage and return spring.However, be sure to pin off the return line to dead head the pump. It needs to reach 18 to 20 psi. This is very important! Also, If the map sensor voltage coming back to the computer is off, this will cause the engine to run lean because the computer may not open the injectors up enough. Also, the fuel injectors could just be bad too!A throttle trunk injection, or TBI, acts almost like a carburetor, except that instead of relying on jets and vacuum to regulate the amount of fuel inbound the intake, a fuel injector, or sometimes two, is used to deliver the correct amount of fuel to the engine. ... Your Chevy may stumble or hesitate at idle at commencement, as the injectors ...Stumble durring initial acceleration. I've got a question about my 1989 Chevrolet K2500 4x4 pickup. Engine is a 5.7L TBI with manual trans with 208000 miles. The problem I'm having is a single engine stumble durring hard or soft acceleration the first time the truck is moved for the day in first gear. The engine will start off fine then cut out ...I had a similiar problem when running my edelbrock 500 cfm on my Clifford intake on my 250. 2001 Carburetors - Edelbrock carb stumbles off idle - I just build me a complete motor with the edelbrock performer RPM package, cam, carb, [Archive] installed edelbrock 1406, dies under load General FSJ Tech. 1. 7L TBI intermittently stumbles/stalls at ... My truck is an 87 R10 with the 305 TBI. When the air conditioning is turned on, the engine will stumble and stall at idle while in gear. Also stumbles and occasionally will stall when first started in the morning. Idles great and runs great when warmed up. The engine turns the A/C compressor fine at higher RPM. Here is what I've done:May 02, 2002 · Discussion Starter · #1 · May 2, 2002 I've got an '88 TBI 350/SM465 combo in my CJ7. The prom on it is from an '88 Blazer with the TBI350/SM465 combo. The motor runs great at idle and revs freely but stumbles just off idle. The EGR valve was replaced and there was no change. There is also a new O2 sensor on it. It doesn't show any codes. All groups and messages ... ...Overall the truck seems to run well with the exception of a hesitation or stumble as I accelerate off idle. Once I get moving it seems to run fine. Recently installed new cap, rotor, plugs, plug wires, in line fuel filter, O2 sensor and one new injector in the TBI.It had a hard start, severe stumble off idle. I did plugs, wires, cap, rotor, air filter and fuel filter. The timing is sitting at 9 degrees. It still had the same symptoms, so I rebuilt the TBI today. I did notice the fuel pressure is at 15psi before I did it, which I thought seems a bit high. Then I noticed someone has been into the fuel ...Similar situation if I don't have throttle in right place for about 10 sec in winter (not my daily, so haven't bothered chasing down high idle with IAC connected) Daily_Project Status: It's been an on/ off affair for years. 1994 Chev astro awd 4.3l 700R.The sub is a 350 TBI, it idles rough, almost like it's running out of fuel and coming off lights it will stall out. Then when I let it sit for a day it drives great and only idles rough. New parts: Fuel pump, fuel filter, EGR valve, radiator, water pump, temp sensor, starter, fuel relay, distributor, cap, rotor, wires, plugs.1989 Dodge D150 318ci TBI 2wd 1/2 ton Automatic Symptoms: Idle raises and lowers, after warming up. Engine stalls when you come to a stop, after the engine warms up. Things I have done: Checked for injector operation. Replaced fuel filter. Checked fuel pressure. Replaced cap, rotor, plugs, and...I have a 92 350 TBI she is hard starting when its cold. I have to turn it over several times in order to get it to start than I have to feather the gas alot in order to keep it running after a few minutes it idles on its own really low idle. Than it smooths out as truck warms up and runs like a champ and when its warm truck starts right up.305 to 350 TBI swap. May 13, 2008, 07:39 PM. I helped a guy form church put a 350 he bought into his 1990 chevy truck. The thing runs, but has a idle and part throttle stumbles. I runs fine at WOT but I am guessing it is lean. We used all of the parts off the 305 on the 350.Short summary: Stumble off idle under hard acceleration. -rebuilt carb. -manifold distributor advance set at 8 degrees BTDC. -idle mixture screws set to the rich side at 2-1/2 turns out. -replaced power valve twice. -replaced accelerator pump twice. -very slight vacuum leak on driver side of throttle shaft.When its cold (as in first thing in the morning), it fires right up and high-idles for a few seconds and runs fine. After the first few seconds, its idles rough. The engine struggles to keep it above 7-800 RPM. When its in gear at idle (like a stop light), it struggles to stay above 500 RPM, and will occasionally stall.I have a 1991 5.7L 350 TBI with 109k miles on it. In park with the engine on, the truck idles completely fine, with or without the brake fully depressed. Once engaged in gear (brake fully depressed), the idle hesitates and drops even before the truck is moving (forward or reverse).I can hear it trying to stumble, but in high gear it doesn't jerk the car so much and when I back off, I can stop right at the limit of the stumble. Key Words: Tune up, tune-up, rough poor idle, low power, power loss, mpg loss, pop, stumble, jerk, jerky, sputtering, hesitation, backfire back fireFollow. Asked by coyboy350 Jan 05, 2015 at 10:20 PM about the 1994 Chevrolet C/K 1500 Silverado Extended Cab 4WD. Question type: General. 94 5.7 tbI I have replaced every sensor on. motor had igniton timing redone. The truck. has full power while driving. Just low idle at. 400rpm and has a slight stutter.What was the cause of the stumble engine? Why does my TBI hesitate on the injector? When does a 1995 Chevy K 1500 350 TBI hesitate? How to solve engine hesitation and stumble problems? What causes engine hesitation and stumble problems on the 90 +? What causes the idle speed to go up or down? Why is my car running rough with no power?When its cold (as in first thing in the morning), it fires right up and high-idles for a few seconds and runs fine. After the first few seconds, its idles rough. The engine struggles to keep it above 7-800 RPM. When its in gear at idle (like a stop light), it struggles to stay above 500 RPM, and will occasionally stall.Update, April 6th, 2018: Early last year, it looked like Holley was going to follow-through on plans to make building a dual-quad throttle body engine easily achieveable.They released a new 2x4 Terminator injector harness that would allow a second Terminator throttle body to be connected via the main harness.Once I start touching the accelerator though (either at a stop or while "cruising" at 1500rpm idle), the engine will stumble. I also thought thought about the TCS. 2 things that tell me it''s not the TCS. 1 - I checked the CTS resistance/temp to a table I had found, and it pretty much matches up.The first few days a stumble off stop, that seems to have cleared a bit, but I do notice it randomly still. It feels like the car is loading up on fuel then clears up with acceleration. Oddly, when first started, the idle starts at 1000RPM, but will climb after warming up or after being driven , or when in Park/Neutral.Aug 03, 2012 · The truck runs fine down the road, although I didn't get on the throttle at speed to see if it starves for fuel. The truck hesitates or stalls off idle. I've used Throttle body cleaner spray with no results. Every where I've read the fuel pressure should be 11-13 psi, but I think that is reference AFTER the TBI regulator. 1995 chevy silverado wont idle and stalls when stopping. i have a 1995 silverado 5.7liter 350 engine, i replaced the motor,the other motor had 225,000plus miles. after replacing the motor it will not idle,and stalls out when stopping, also noticed that the motor surges, when applying the throttle it will rev up,but it will try to die off unless ...Next, turn the engine off and disconnect the idle control motor under your hood. To all those who use the Fitech 600 system, I need your help; I have a slight stumble with a slight lean condition on acceleration on a smooth throttle input; The AFR at that time is about 15:1 16:1, and corrects itself quickly to 13:1 Also have noticed a exhaust ...Mar 25, 2013 · No power and stumble off idle. Post by aaimada » Sun Apr 27, 2014 5:55 pm lsvtec 81.25mm 10.2:1 compression gsc t1 cams zeroed. 1000cc grams injectors, 70mm throttle body, skunk 2 pro intake manifold, exedy twin disc clutch, ITR transmission. running N/A for now trying to brake in the motor and figure out this lack of power off idle. Jan 10, 2021 · #1 It was suggested to check valve lash. the engine had 5oo miles on it so I pulled the valve covers and set them to Chilton's specs. #2 at idle Tested intake for vacuum leaks with carb cleaner. (3 times) no difference. #3 Changed Map sensor. #4 Changed Idle air control valve #5 changed the injectors even though they looked great. The GM TBI (Throttle Body Injection) system uses a pair of low pressure fuel injectors mounted above the throttle body opening. and I did have a stumble off idle. 7 GM Tbi w Dual Air Cleaner Studs . Serving our valued customers for over 30 years. 87-95 Chevy Silverado TBI 350 Chevy Engine 400 HP 87-95 Chevy Silverado TBI 350 Chevy Engine 400 HP.The idle air control valve is responsible for managing the engine idle speed. The valve is a major management component of the engine which will either decrease or increase the number of revolutions per minute, depending on what the current operating conditions call for.I installed the Howel TBI on my '85 CJ7 with the 258. I am about to see if it smogs, I have been driving it to get the computer settled in but I am concerned about a stumble coming off idle. It idles at 750 and runs well at the upper RPM range but starting off in first it'll stumble and feels...There's a stumble at idle, but there really isn't any indication that the idle is too low. Everywhere I've read says that the idle is supposed to be around 800rpm and that seems to be where it's at. It's hard to tell because of how the stock tach is labeled. It seems it stumbles moreso when coming to a stop sign off a higher rpmRe: 95 Chevy S-10 4.3L TBI - Idle troubles. Another Update, It looks like internet and my repair book is wrong on the subject of MAP sensor voltage. I was told that the MAP sensor puts out 1.2 - 1.6 volts at idle and around 4.2 - 4.5 at Wide open. This data is wrong.I'm having a problem with my idle speed on coast down from any RPM above 1000-1500 or so, back down to idle. TPI 350 has new IAC sensor and Fuel Pressure is set at aprox 52 PSI. Timing is set to 0* at idle with electronic advance disabled. If I set the TPS as called for, .45-.55 volts, Car wont...81 Posts. Discussion Starter · #1 · Apr 14, 2018. Hi there, Finally got my Chevelle out of the garage with the new engine this morning. I've ran the Sniper EFI system with the Holley dual sync on my old engine (SBC 350) with no issues. I broke in the cam on the new engine (SBC 400) with the sniper and dual sync, also with really no issues.You might want to check the EGR valve and for vacuum leaks. check the air idle solenoid on the TBI. sometimes you can remove them and clean the carbon from them using gum cutter. if this doesnt work, check the knock sensor. if this does not work you might have a internal vacuum leak. ajs79lincoln 12-19-2004, 10:05 PM1. 4.3L Vortec ICV and TPS Failure. The idle control valve ("ICV") and throttle position sensors ("TPS") are prone to failure on all 4.3 engines, which can result in poor idling, engine stalling, bad acceleration, and other low-rpm running problems. The idle control valve sits on the throttle body and is responsible for adjusting the ...Now it has a erratic idle. When cold the engine idles around 1400 rpm, when giving it gas the engine seems to stumble then takes off, then stumbles and goes. It's noticeable when driving. Once the motor is warmed up the idle is around 500 rpm but it acts like it misses, then idles up to 700 rpm. This when in gear.Oct 13, 2014 · I was fighting this annoying off idle stumble and hesitation... Tried different pump cams and discharge nozzles. Never quite helped. I had already ensured that the accelerator pump nozzle was working correctly and the arm and lever clearance was good. I ordered the 50cc accelerator pump... Mar 22, 2013 · How can you tell if an off-idle stumble is caused by a lean or a rich condition? A carb running rich, as well as a carb running lean, can cause an off-idle stumble or hesitation upon acceleration. To narrow it down, tap the roll pin out of the accelerator pump lever by using a small pin punch or a small finish nail. I actually use a small ... Once I start touching the accelerator though (either at a stop or while "cruising" at 1500rpm idle), the engine will stumble. I also thought thought about the TCS. 2 things that tell me it''s not the TCS. 1 - I checked the CTS resistance/temp to a table I had found, and it pretty much matches up.Location Colorado Jun 19, 2006 #1 TBI is surging with steady part throttle in open loop when cold. Especially when it's been driven - shut down for an hour - and restarted. The surge is like a whup-whup-whup-whup until I add throttle and rev it out. It goes away after I drive it for a minute or it warms up to closed loop.Here are the qualifiers for EGR on a 90 Chev 350 TBI Code: Select all EGR On, (% TPS) 3.1 % TPS EGR Off, (% TPS) 2 % TPS EGR Off, (Speed) 0 MPH EGR On, (Speed) 0 MPH EGR Enable Coolant Temp Threshold 49 Deg. C Low MAP EGR Off, (MAP) 28.1 MAP Low MAP EGR On, (MAP) 31.1 MAP Here are the spark/fuel correction tables for EGR on a 90 Chev 350 TBIWhich TBI ECM are you using ... I've been thinking you have the 1993 ECM? 1993 is the start of faster 8192 Baud Rate for automatic transmission GM Pickups. The 1993 ECM has two spark tables, and two fuel tables, near idle / off idle. The faster 8192 Baud Rate ECM / PCM does not have a neutral / park switch input, so it needs a VSS.Aug 09, 2012 · Every once in a while I'll go to take off when the light turns green and the bike will stumble just off idle and die. It usually happens while I'm slowly releasing the clutch and simultaniously giving the bike throttle. It's like it hits a weird spot in the fueling and the bike can't take any load while idling so it just stalls when the ... All groups and messages ... ...TBI Assembly 900 CFM 85 lb/hr Complete 1 534-173 2 Avenger EFI ECU and Handheld 1 554-116 3 Main Power Harness 1 558-308 4 Avenger EFI TBI Wiring Harness 1 558-100 5 Inline Pump 1 N/A 6 Metal Fuel Filter 1 562-1 7 Fuel Filter (WIX 33033) 1 N/A 8 Fuel Filter Clamp 1 N/A 9 Fuel Pump Block-Off Plate & Gasket 1 12-813TBI is a wet manifold (wet with fuel flowing thru it) and so if the engine is running cold, there can be issues with the vapor condensing into liquid. My TBI truck stumbles and coughs when its cold, for a little bit until the intake warms up and even the TBI has internal waterflow heating to help with vaporization. When warm it runs like a champ.1. 4.3L Vortec ICV and TPS Failure. The idle control valve ("ICV") and throttle position sensors ("TPS") are prone to failure on all 4.3 engines, which can result in poor idling, engine stalling, bad acceleration, and other low-rpm running problems. The idle control valve sits on the throttle body and is responsible for adjusting the ...This can cause a very uneven idle, which can jump up and down, and the engine may also shut off on idle. Re: 1995 TBI 350 with 214k stumbles a little at idle, otherwise runs great After further reading, I'm starting to lean on the IAC being the problem. Also stumbles and occasionally will stall when first started in the morning.Search: 350 Tbi Stumbles At Idle. About Tbi Idle At 350 StumblesDanny, I have a severe stumble/hesitation off idle. My program shows AE vs TBI in percentages. ajs79lincoln. i am no longer gettin the fuel leak out of the fpr, but it still hesitates a little bit. Feb 10, 2010 · Automotive Recalls and Technical Service Bulletins for 1991 Chevrolet Caprice V8-350 5. truck starts then dies SOLVED. I can hear it trying to stumble, but in high gear it doesn't jerk the car so much and when I back off, I can stop right at the limit of the stumble. Key Words: Tune up, tune-up, rough poor idle, low power, power loss, mpg loss, pop, stumble, jerk, jerky, sputtering, hesitation, backfire back fireDo this by slightly by turning the primary idle speed screw out (counter-clockwise) about a half turn. This should slow the engine down. Then shut the engine off long enough for the TPS to reset. Restarting the engine should reveal an increase in the IAC steps to perhaps around 8-10.The GM TBI (Throttle Body Injection) system uses a pair of low pressure fuel injectors mounted above the throttle body opening. and I did have a stumble off idle. 7 GM Tbi w Dual Air Cleaner Studs . Serving our valued customers for over 30 years. 87-95 Chevy Silverado TBI 350 Chevy Engine 400 HP 87-95 Chevy Silverado TBI 350 Chevy Engine 400 HP.The problem is the engine will start and idle, but won't run anything past a fast idle before it stumbles and dies. We crank it over and eventually it starts but runs through the same problem. The engine is a basically stock 454 with a Performer RPM dual plane intake, a 750 cfm Holley, and headers.When driving it shudders erratically at idle when in gear (ie: at a stoplight). 350 Tbi Stumbles At Idle from 250hp to 260hp the fuel pressure should be bumped up to 13-14psi on stock 350 truck injectors which will change their flow rating to 60lb/hr. Jump to Latest Follow 1 - 20 of 36 Posts.May 14, 2017 · At idle the the rpms fluctuate up/down, with the RPMS ranging between about 750-900. There is a constant 150-200 rpm bounce. The vehicle starts w/o issue but in gear or park it has the rough idle. When in gear, accelerating smoothly it does so evenly but it feels under powered. At 60 mph it needs to down shift to go over even small over passes. Discussion Starter · #1 · May 2, 2002 I've got an '88 TBI 350/SM465 combo in my CJ7. The prom on it is from an '88 Blazer with the TBI350/SM465 combo. The motor runs great at idle and revs freely but stumbles just off idle. The EGR valve was replaced and there was no change. There is also a new O2 sensor on it. It doesn't show any codes.No effect at idle, unless your previous PV had a hole in it, and you tried to tune the idle while the PV was dumping in fuel. Setting the idle mixture should not be a big deal. Turn each screw in until you feel a stumble, then back off a little. Best lean idle. You should be able to stall the engine with the idle screws, if you have the idle ...Lifted_Bowtie. Hey guys, I finally got my 350 up and running, she purrs like a kitten and is stronger than EVER! I have 70 to 75 pounds oil pressure cold and 40 - 45 warm and 70 pounds when i get on the pedal! Although im having trouble with the tbi i assume. the engine will stall when coming to stop at a stop light, but it stalls and shuts off ...Step 4. Unplug the IAC valve located on the passenger side, rear of the throttle body. Start the engine. Insert a T-30 size Torx driver into the Idle adjustment screw that is located behind the plug removed earlier. Turn the screw to adjust the idle speed to 650 RPM +/- 50 RPM. Turn off the engine and disconnect the negative battery terminal ...Cliff-notes below. 1995 TBI 5.7L, about 235,000 miles on original motor. A few weeks ago on the way home from work, my 95 began stumbling/misfiring under load. As long as I stayed under about 1/4 throttle, it was okay. Getting closer to home, it began backfiring through the exhaust. Didn't...I have a 1991 5.7L 350 TBI with 109k miles on it. In park with the engine on, the truck idles completely fine, with or without the brake fully depressed. Once engaged in gear (brake fully depressed), the idle hesitates and drops even before the truck is moving (forward or reverse).Jul 25, 2016 · Sweden. Sometimes the the idle jets (idle tubes) on the 1406 are a bit small for the application and you get off idle stumble, I guess it's the same situation on the 1411, unfortunately there's no changeable idle jets so you have to drill them out a tiny step carefully by hand (hand chuck). You find the idle tube on the 1st cluster: Jul 26, 2016. I currently have a problem just off idle with very slight throttle opening of going lean. The piston travel is altered with a threaded "double-D" screw that is barely seen here (A). The problem I have with my 63 Impala is what holley calls a "tip in" stumble. Order today! Chevy Truck 454 Tbi Throttle Body To Carb Intake Factory Adapter Plate 7.#1 It was suggested to check valve lash. the engine had 5oo miles on it so I pulled the valve covers and set them to Chilton's specs. #2 at idle Tested intake for vacuum leaks with carb cleaner. (3 times) no difference. #3 Changed Map sensor. #4 Changed Idle air control valve #5 changed the injectors even though they looked great.I had a similiar problem when running my edelbrock 500 cfm on my Clifford intake on my 250. 2001 Carburetors - Edelbrock carb stumbles off idle - I just build me a complete motor with the edelbrock performer RPM package, cam, carb, [Archive] installed edelbrock 1406, dies under load General FSJ Tech. 1. 7L TBI intermittently stumbles/stalls at ... May 05, 2014 · 350 2 Barrel Issue - (Off idle Stumble) Discussion in 'The Bench' started by ToddsGS, May 5, 2014. Page 2 of 2 < Prev 1 2. Chris Lance Platinum Level Contributor. Follow. Asked by coyboy350 Jan 05, 2015 at 10:20 PM about the 1994 Chevrolet C/K 1500 Silverado Extended Cab 4WD. Question type: General. 94 5.7 tbI I have replaced every sensor on. motor had igniton timing redone. The truck. has full power while driving. Just low idle at. 400rpm and has a slight stutter.So I have a 74 with Howell TBI the PO installed. I have a miss or a stumble best way I know to describe it. I have new coil, spark plugs, ignition wires,points, and O2 sensor all with less than 50 miles or 3 hours run time. I had a bad alternator and upgrade to a 3g truck seemed to wake up...If you suspect that the EGR valve is behind your engine's rough idle condition, this tutorial will help you to troubleshoot it with 2 simple tests. NOTE: This tutorial covers the EGR valve of the 1987-1995 throttle body fuel injection (TBI) system of the 4.3L, 5.0L, and 5.7L GM engines.A number of the early TBI vehicles I've driven have a fairly aggressive throttle tip-in. Sometimes, if you can modulate the throttle with a velvet slipper, you can actually get the engine to stumble a little between on and off idle instead of lurch. But it's never a particularly smooth transition.It will start normally and idle fine (with a barely noticeable misfire). It behaves pretty well until it starts to warm up. After warming, the engine starts missing significantly when I give it a little throttle (neutral or in gear). If I keep a light throttle in neutral the miss will get worse until it barely keeps going.Re: Low RPM Stumble. Post. by rickb794 » Thu Nov 05, 2015 4:15 pm. The default spark table is usually good some motors will want more/less timing at idle and most will see gains if part throttle cruise area advance is raised. At 8.7 CR you may be able to get more aggressive with the spark. As long as it is not boosted. Your off idle stumble is most likely the accelerator pump or the adjustment of it and no amount of tuning or timing is going to fix that so try to put that out of your mind for now. Just get it to run, then rebuild the carb. Bill _____ '65 Buick Skylark, 406 sbc, 10.07 comp, ported Trick Flow 195 heads, RPM Air gap, Holley 3310, Straub HR .547 ...Jun 16, 2012 · OK so ive developed a pretty good stumble/hesitation that usually occurs off idle and lower rpm range. Its a 2000 2.5 manual. The car has 190k on it and the motor has approx. 2500 miles on it. I havent checked the spark plugs yet, but will 2morrow. Its got autolite wires on it (not a big fan... Engine started normally, idled to about 800 briefly, then idled up and down about three times, then settled at 800 approx. Let it warm. and turned it off. Restarted back 10 seconds later and starts with a very low, barely running idle that over 20 seconds slowly increases back to 800-900. Does that on each warm-hot start.Subject: Idle? Date: Mon, 13 Apr 1998 10:54:39 +1200. Yep, its FIXED! Thanks Steve, for that draft of the dissertation on how to fix idle/stumble. It turned out to be the throttle sensor connector, managed to remove some almost chrome flake looking stuff off the make connectors! Tightened it all back up, and threw it on.The '7747 uses other variables to switch between the Idle tables and off idle tables, one of those parameters being vehicle speed. ... I know my 90 Z71 tbi seems like it stumbles if I do a quick to the mat stab ... something I used to test quadrajets I rebuilt with. ... Truly progressive TBI with operation on only one TB at idle would be neat ...no, does not idle at 2000 rpm's idles around 800-1000 when warm, it stumbles sometimes at the 2000 rpm mark, From looking over some other threads I guess the pressure is fine. Some other people have noted that when it hot out pressure drops to 5 psi when at idle, which is what mines does. not sure why it's only at 2000 rpm that the engines ...Stumble durring initial acceleration. I've got a question about my 1989 Chevrolet K2500 4x4 pickup. Engine is a 5.7L TBI with manual trans with 208000 miles. The problem I'm having is a single engine stumble durring hard or soft acceleration the first time the truck is moved for the day in first gear. The engine will start off fine then cut out ...Oct 20, 2011 · Off Idle Stumble. Discussion in 'Motorcycle Tech Talk' started by Gunnernate, Oct 20, 2011. Page 1 of 2 1 2 Next > Gunnernate New Member. Joined: Oct 20, 2011 ... Off idle stumble Off idle stumble. KeyKeeper. 123. KeyKeeper. 123. Post Dec 27, 2016 #1 2016-12-27T16:07. ... Going to use a TBI dist just for the inductive pickup and small cap, dont need a mech advance so seems like a good fit. Thumperdart. 565 4. Thumperdart. 565 4. Post Dec 29, 2016 #10 2016-12-29T16:05.Search: 350 Tbi Stalling. About Tbi 350 StallingI'm having a problem with my idle speed on coast down from any RPM above 1000-1500 or so, back down to idle. TPI 350 has new IAC sensor and Fuel Pressure is set at aprox 52 PSI. Timing is set to 0* at idle with electronic advance disabled. If I set the TPS as called for, .45-.55 volts, Car wont...Sep 08, 2009 · Discussion Starter · #1 · Sep 8, 2009. Well I seem to have a little miss in my Idle at low RPM,it seems like it's mostly when I let off gas and come to a stop or when I am just starting to go from a stop. This is only like one missed fire just a real quick little stumble. The rest of the time the Grizz runs fine, My air cleaner is nice and ... Oct 02, 2017 · My bike has developed a very slight , just off idle stumble. Just the first instant when you twist the throttle. It hasn't always done this and unfortunately it is usually at the same exact time I am starting to release the clutch and it is making it difficult to pull away from a stop smoothly. Otherwise the bike runs great. Basicly, I have limited power, off idle stumble, and a slight pop out of the exhaust when shifting. It takes alot to get the rpms up and seems to lose power about 4500 rpm. When idling, a distinctive stumble is heard and throttle response is not that great. Also, if I adjust mixture needles for optimum vacuum, the idle shoots up and I can't get ...Apr 30, 2014 · Concord,NC. May 1, 2014. #5. The engine is originally from a 1993 Suburban, I have some specs on the engine, the block has been bored .040 over,heads resurfaced .007, it has flat top pistons (h-345acp-040), a (cs-1014-r) camshaft, a tbi spacer and injector spacer and a lower temp thermostat. I also installed a complete accel ignition system ... Fuel pressure on a TBI unit should stay constant under all throttle conditions. There should be less than 1 psi of pressure difference from idle to WOT operation of the TBI unit. A pressure drop of more than 1 psi under these conditions indicates an issue with the fuel delivery system.Search: 350 Tbi Stalling. About Tbi 350 StallingSearch: 350 Tbi Stumbles At Idle. About Tbi Idle At 350 StumblesHere are the qualifiers for EGR on a 90 Chev 350 TBI Code: Select all EGR On, (% TPS) 3.1 % TPS EGR Off, (% TPS) 2 % TPS EGR Off, (Speed) 0 MPH EGR On, (Speed) 0 MPH EGR Enable Coolant Temp Threshold 49 Deg. C Low MAP EGR Off, (MAP) 28.1 MAP Low MAP EGR On, (MAP) 31.1 MAP Here are the spark/fuel correction tables for EGR on a 90 Chev 350 TBISearch: 350 Tbi Stalling. About Tbi 350 StallingThe problem is the engine will start and idle, but won't run anything past a fast idle before it stumbles and dies. We crank it over and eventually it starts but runs through the same problem. The engine is a basically stock 454 with a Performer RPM dual plane intake, a 750 cfm Holley, and headers.1995 K1500 350TBI. Tall gears. All new ignition except for coil. New Napa fuel filter. New air filter. Truck runs great when cold, the following only happens at operating temp (195 on the gauge). Idles fine, seems to run fine above 1,000. When the light turns green and you ease into the gas, it stumbles.I had a similiar problem when running my edelbrock 500 cfm on my Clifford intake on my 250. 2001 Carburetors - Edelbrock carb stumbles off idle - I just build me a complete motor with the edelbrock performer RPM package, cam, carb, [Archive] installed edelbrock 1406, dies under load General FSJ Tech. 1. 7L TBI intermittently stumbles/stalls at ... Lifted_Bowtie. Hey guys, I finally got my 350 up and running, she purrs like a kitten and is stronger than EVER! I have 70 to 75 pounds oil pressure cold and 40 - 45 warm and 70 pounds when i get on the pedal! Although im having trouble with the tbi i assume. the engine will stall when coming to stop at a stop light, but it stalls and shuts off ...So, one of the most common symptoms associated with a problematic idle air control valve (IAC) is, irregular idle speed. Because, the (IAC); is programmed to regulate and maintain the engine idle speed, at a constant rate. If the valve fails or has any issues, it can cause the idle speed to be thrown off. This may result in an unusually high or ...I'm having a problem with my idle speed on coast down from any RPM above 1000-1500 or so, back down to idle. TPI 350 has new IAC sensor and Fuel Pressure is set at aprox 52 PSI. Timing is set to 0* at idle with electronic advance disabled. If I set the TPS as called for, .45-.55 volts, Car wont...1990 Jeep Wrangler 2.5L Engine Bucks and Stumbles ... when you do get ready to speed up it literally will not take the gas itll start jumping and bucking we can switch it off give 30 mins and it cranks and runs fine.problem 3 at highway speeds when you hit a hill and try yo accelerate itll kinda spit like theres water in the gas.ive talked to 2 ...Update, April 6th, 2018: Early last year, it looked like Holley was going to follow-through on plans to make building a dual-quad throttle body engine easily achieveable.They released a new 2x4 Terminator injector harness that would allow a second Terminator throttle body to be connected via the main harness.Hi folks, When the truck is stopped and in gear, and I put my foot lightly on the gas, I'll get a stumble or bog - like the timing suddenly retards - and then I'll take off quick, as soon as the engine is out of that little area around 1000-1200 RPM. If the engine is really cold, and I don't give the idle time to settle out after starting, that bog will turn into a miss or a CLUNK the first time.Throttle response is great with no hint of off idle hesitation or full throttle stumble. Cons: The system will run returnless but it has a tendency to vapor lock in this configuration as ambient air temperatures rise in the summer months.My project is coming along but still has some issues. One is that when idling or accelerating from a stop, as soon as you crack the throttle and manifold vacuum drops, it really stumbles. Once the vacuum catches up a little, it seems to be okay. Taking off from a stop seems to exacerbate the issu...(09-20-2016, 02:31 AM) sspence81 Wrote: 88 1/2 Samurai that has been converted to EFI with a 89/90 ECU and wiring harness. but what was the donor car? Is it TBI EFI? Starts perfect and idles great. Idles down after a few minutes fine. Runs and drives great until it gets hot.2. Engine won't idle smoothly, idles too slowly, or stalls. If you start to experience engine misfires, stalling, or rough idling when the car is stopped, it can also be a warning sign of a failing TPS. You don't want to wait to get this checked out! If the idling appears off, it means the computer is unable to identify the fully shut throttle.Similar situation if I don't have throttle in right place for about 10 sec in winter (not my daily, so haven't bothered chasing down high idle with IAC connected) Daily_Project Status: It's been an on/ off affair for years. 1994 Chev astro awd 4.3l 700R.Makes idle in park around 1700 rpms. In 4low with idle adjusted up, truck still stalls when dropped in gear, unless throttle finesse is applied. 2) Still runs rich at idle according to checking the plugs after being brought up to temp. The only good thing is that the truck runs pretty darn good once warmed up, off idle. roasting 42's.lol what hasn't been done to this recently, a little history, got the truck CHEAP, cause someone had tried to steal it, tried cause all they did was f'up the locks and steering column. was going to drop the motor into the 87 blazer i had, but that one burned in a fire, and since the rest of the truck wasn't so bad just decided to fix it up instead. the motor and tranny are recent rebuilds, can ...1995 Chevy S10 4.3 V6 TBI VIN Z engine 238k miles. If anyone remembers I had my engine replaced with a used one little over a year ago. I had engine stumbling with light throttle just off of idle. The engine had a coolant leak internally and the EGR was sticking according to the mechanic. He just cleaned the EGR valve then but I replaced it later. Anyway, I started getting similar problems ...Throttle response is great with no hint of off idle hesitation or full throttle stumble. Cons: The system will run returnless but it has a tendency to vapor lock in this configuration as ambient air temperatures rise in the summer months.81 Posts. Discussion Starter · #1 · Apr 14, 2018. Hi there, Finally got my Chevelle out of the garage with the new engine this morning. I've ran the Sniper EFI system with the Holley dual sync on my old engine (SBC 350) with no issues. I broke in the cam on the new engine (SBC 400) with the sniper and dual sync, also with really no issues.1995 K1500 350TBI. Tall gears. All new ignition except for coil. New Napa fuel filter. New air filter. Truck runs great when cold, the following only happens at operating temp (195 on the gauge). Idles fine, seems to run fine above 1,000. When the light turns green and you ease into the gas, it stumbles.Jan 10, 2021 · #1 It was suggested to check valve lash. the engine had 5oo miles on it so I pulled the valve covers and set them to Chilton's specs. #2 at idle Tested intake for vacuum leaks with carb cleaner. (3 times) no difference. #3 Changed Map sensor. #4 Changed Idle air control valve #5 changed the injectors even though they looked great. Jun 16, 2012 · OK so ive developed a pretty good stumble/hesitation that usually occurs off idle and lower rpm range. Its a 2000 2.5 manual. The car has 190k on it and the motor has approx. 2500 miles on it. I havent checked the spark plugs yet, but will 2morrow. Its got autolite wires on it (not a big fan... Now it has a erratic idle. When cold the engine idles around 1400 rpm, when giving it gas the engine seems to stumble then takes off, then stumbles and goes. It's noticeable when driving. Once the motor is warmed up the idle is around 500 rpm but it acts like it misses, then idles up to 700 rpm. This when in gear.The off idle throttle response is kind of rough, as I go to let the clutch out from a stop it will stumble or sputter a bit before it clears itself and will run perfectly smooth above 1200rpms or so. It has a comp 270ahr with the stock tuning right now, I removed the hypertech tuning before I ran it for the first time but I will be doing a ...Fuel Trims LS1 V8 0 - 15 defined by the LTFT RPM and MAP boundaries 16 - Idle PN (AC on) 17 - Idle PN (AC off) 18 - Idle InGear (AC on) 19 - Idle InGear (AC off) 20 - Idle. In this guide, you will learn about Chevy Mass Air Flow (MAF) sensor problems, common symptoms, and how to replace the MAF sensor on a Chevy. 7) with TBI.305 to 350 TBI swap. May 13, 2008, 07:39 PM. I helped a guy form church put a 350 he bought into his 1990 chevy truck. The thing runs, but has a idle and part throttle stumbles. I runs fine at WOT but I am guessing it is lean. We used all of the parts off the 305 on the 350.Jul 25, 2016 · Sweden. Sometimes the the idle jets (idle tubes) on the 1406 are a bit small for the application and you get off idle stumble, I guess it's the same situation on the 1411, unfortunately there's no changeable idle jets so you have to drill them out a tiny step carefully by hand (hand chuck). You find the idle tube on the 1st cluster: Jul 26, 2016. 1995 K1500 350 TBI Stumble was created by 93Rubie. Have a odd one and looking for any ideas. Has a stumble/misfire only at hot idle. More noticeable in gear. Fuel trims are about 128/134 so good. 02 sensor cycling rich and lean. Spark is solid from coil on scope and cylinder drop test. Each cylinder drops more or less equal rpm at idle.The idle mixture screws (Holley 750 vac sec) are only out 1/4 to 1/2 turn and it idles rich, it also seem to have a slight off idle stumble when you snap the throttle. I pulled the plugs and they are black and sooty the gaps were all over the place so I regapped them to .045 for the HEI.Re: Off idle stumble and AE tuning. As gtmdriver suggested I think your AE is adding to much fuel, this can cause o2 sensor to show lean when it is actually rich causing a stumble. Turn AE off first and tune VE for slow to moderate tip ins off idle. Once you have this dialed in then you can start tuning AE.When the warning light goes out, the system will resume as normal. Coverking Neosupreme Seat Covers From 8. They are good off road and still a nice highway vehicle. 8 5. Spark Plugs- One of the absolute most commonRuns perfectly normal off idle and in Park but idles rough when stopped in gear. So, you are faced with diagnosing a stored a code ... Mascobe. 1995 Silverado, 2wd Air, 5.7L. Stumbles and runs rough at lower throttle positions (just off idle). Idle is good and WOT seems normal (will spin the rear tires and sounds like it's hitting on all 8). I did find the rubber link hose to the MAP sensor and canister purge line were cracked which caused some surging while driving.Subject: Idle? Date: Mon, 13 Apr 1998 10:54:39 +1200. Yep, its FIXED! Thanks Steve, for that draft of the dissertation on how to fix idle/stumble. It turned out to be the throttle sensor connector, managed to remove some almost chrome flake looking stuff off the make connectors! Tightened it all back up, and threw it on.81 Posts. Discussion Starter · #1 · Apr 14, 2018. Hi there, Finally got my Chevelle out of the garage with the new engine this morning. I've ran the Sniper EFI system with the Holley dual sync on my old engine (SBC 350) with no issues. I broke in the cam on the new engine (SBC 400) with the sniper and dual sync, also with really no issues.1995 Chevy S10 4.3 V6 TBI VIN Z engine 238k miles. If anyone remembers I had my engine replaced with a used one little over a year ago. I had engine stumbling with light throttle just off of idle. The engine had a coolant leak internally and the EGR was sticking according to the mechanic. He just cleaned the EGR valve then but I replaced it later. Anyway, I started getting similar problems ...Off Idle Stumbles Was curious a good place to start with some off idle stumble when the car gets some heat into it. It seems like leaving a stoplight over 170° of oil or water temp it wants to stumble & hesitate. It's a 9.5:1 1400 RWHP E85 TT SBC, everywhere over 1800 RPM seems to be OK. On the throttle or tip-in below that isn't happy.Jul 25, 2016 · Sweden. Sometimes the the idle jets (idle tubes) on the 1406 are a bit small for the application and you get off idle stumble, I guess it's the same situation on the 1411, unfortunately there's no changeable idle jets so you have to drill them out a tiny step carefully by hand (hand chuck). You find the idle tube on the 1st cluster: Jul 26, 2016. The resistance on the injectors read 0. 003 on the 3 scale. I don't know if that means the is only 3 thousands ohms on the injector or 3 ohms on the injector. Digital always confuses me. Before this happened the engine run, but the idle was bad. It didn't stall but it was a little rough. It run on the road OK, the idle was just a little rough.1 day ago · MIXTURE – IDLE CUT-OFF 4. 2cc Gas 2-Stroke Cycle Backpack Leaf Blower with Tube Throttle Retail price0 -Pb755st-ECHO 233 MPH 651 CFM 63. Scooter runs now, and I can take it to full throttle when it's on the Aug 27, 2010 · I use Castrol TTS (2 Stroke, Fully Synthetic) Oil, the Carb is a Dell'Orto 17. Jeep idles high when started, goes down to normal idle, and once warmed up will idle rough and low, 600-700. Idling will not cause her to die though, only movement and shifting. Jeep will not start back up once shes been running or after she stalls unless she sits for 10-15 minutes, and she will start fine but a little rough.Do this by slightly by turning the primary idle speed screw out (counter-clockwise) about a half turn. This should slow the engine down. Then shut the engine off long enough for the TPS to reset. Restarting the engine should reveal an increase in the IAC steps to perhaps around 8-10.used throughout GM up until about 1995. <c>Do not get one off a super or turbo charged engine, or from pre TBI cars such as the 307 Olds engine you will be looking for to find a suitable distributor. They are manifold differential pressure sensors as opposed to absolute pressure sensors. <c>Output is a bit Off Idle Stumble (MY98 2.5GT) Normally Aspirated PowertrainIf you suspect that the EGR valve is behind your engine's rough idle condition, this tutorial will help you to troubleshoot it with 2 simple tests. NOTE: This tutorial covers the EGR valve of the 1987-1995 throttle body fuel injection (TBI) system of the 4.3L, 5.0L, and 5.7L GM engines.Jan 10, 2021 · #1 It was suggested to check valve lash. the engine had 5oo miles on it so I pulled the valve covers and set them to Chilton's specs. #2 at idle Tested intake for vacuum leaks with carb cleaner. (3 times) no difference. #3 Changed Map sensor. #4 Changed Idle air control valve #5 changed the injectors even though they looked great. UltraTwist. I bought Dodge b250 few months ago, it's 1989 TBI 318 and I'm spending a lot of time trying to solve his puzzle. my 318 have big problem with Idle RPM and throttle response. Idle goes up and down about 100RPM, it happen suddenly and quite often. Other thing is that it have huge lag/bog when I hit the accelerator pedal (under load ...outbackken July 6, 2016, 4:32am #5. The off idle stumble usually occurs from a dead stop. One or two seconds where the engine just shakes a bit before producing power. I have noticed some times too where moving with light throttle there seems to be no power and I have to push down hard on the pedal to get a response. Overall the truck seems to run well with the exception of a hesitation or stumble as I accelerate off idle. Once I get moving it seems to run fine. Recently installed new cap, rotor, plugs, plug wires, in line fuel filter, O2 sensor and one new injector in the TBI.81 Posts. Discussion Starter · #1 · Apr 14, 2018. Hi there, Finally got my Chevelle out of the garage with the new engine this morning. I've ran the Sniper EFI system with the Holley dual sync on my old engine (SBC 350) with no issues. I broke in the cam on the new engine (SBC 400) with the sniper and dual sync, also with really no issues.Danny, I have a severe stumble/hesitation off idle. My program shows AE vs TBI in percentages. ajs79lincoln. i am no longer gettin the fuel leak out of the fpr, but it still hesitates a little bit. Feb 10, 2010 · Automotive Recalls and Technical Service Bulletins for 1991 Chevrolet Caprice V8-350 5. truck starts then dies SOLVED.Sep 19, 2005 · Replaced the Idle control doohickey screwed into the tbi- $35.00 no help. Got desperate and replaced the MAP sensor $37.00- no help. Finally did something that I should have done from the start. used throughout GM up until about 1995. <c>Do not get one off a super or turbo charged engine, or from pre TBI cars such as the 307 Olds engine you will be looking for to find a suitable distributor. They are manifold differential pressure sensors as opposed to absolute pressure sensors. <c>Output is a bit Short summary: Stumble off idle under hard acceleration. -rebuilt carb. -manifold distributor advance set at 8 degrees BTDC. -idle mixture screws set to the rich side at 2-1/2 turns out. -replaced power valve twice. -replaced accelerator pump twice. -very slight vacuum leak on driver side of throttle shaft.Once I start touching the accelerator though (either at a stop or while "cruising" at 1500rpm idle), the engine will stumble. I also thought thought about the TCS. 2 things that tell me it''s not the TCS. 1 - I checked the CTS resistance/temp to a table I had found, and it pretty much matches up.Oct 02, 2017 · My bike has developed a very slight , just off idle stumble. Just the first instant when you twist the throttle. It hasn't always done this and unfortunately it is usually at the same exact time I am starting to release the clutch and it is making it difficult to pull away from a stop smoothly. Otherwise the bike runs great. Update, April 6th, 2018: Early last year, it looked like Holley was going to follow-through on plans to make building a dual-quad throttle body engine easily achieveable.They released a new 2x4 Terminator injector harness that would allow a second Terminator throttle body to be connected via the main harness.When you notice a Stumble, Back off the throttle a little 1/8-1/4: 1. If it surges ahead your Lean 2. If it stumbles and recovers your Rich Now depending on where in the Throttle position this happens Different settings have to be done: 1. If it stumbles as your starting off - Adjust your Air/Fuel Mixture 2.The GM TBI (Throttle Body Injection) system uses a pair of low pressure fuel injectors mounted above the throttle body opening. and I did have a stumble off idle. 7 GM Tbi w Dual Air Cleaner Studs . Serving our valued customers for over 30 years. 87-95 Chevy Silverado TBI 350 Chevy Engine 400 HP 87-95 Chevy Silverado TBI 350 Chevy Engine 400 HP.The problem is the engine will start and idle, but won't run anything past a fast idle before it stumbles and dies. We crank it over and eventually it starts but runs through the same problem. The engine is a basically stock 454 with a Performer RPM dual plane intake, a 750 cfm Holley, and headers.Next, turn the engine off and disconnect the idle control motor under your hood. To all those who use the Fitech 600 system, I need your help; I have a slight stumble with a slight lean condition on acceleration on a smooth throttle input; The AFR at that time is about 15:1 16:1, and corrects itself quickly to 13:1 Also have noticed a exhaust ...no, does not idle at 2000 rpm's idles around 800-1000 when warm, it stumbles sometimes at the 2000 rpm mark, From looking over some other threads I guess the pressure is fine. Some other people have noted that when it hot out pressure drops to 5 psi when at idle, which is what mines does. not sure why it's only at 2000 rpm that the engines ...i have the same problem with my roady. sitting at idle it will begin to hesitate and stumble but then fine when you drive off. exept mine throws a code 44 for lean exhaust. i was thinking it could be bad lash on an exhaust valve because i hear a tick now. i also the difference in the drivers side exhaust out of the pipe. i will check the ...May 22, 2019 · Of course assuming at this point does not get answers. as to the other truck getting better fuel mileage it was a 1600 Loadstar, with a 345 set up with the same pro jection system, and a 4 speed, with two speed rear, and in high, ratio of 5.8, the bus is 5.14 in high on the rear. The 1600 was grossing 26,000 lbs, and the bus is 18,000lbs normal ... I have a stock 302 with an edlbrock manifold, Holley truck avenger, pertronics ignition. I have a wicked flat spot off idle (It has stalled) and a stumble off decel at about 20 mpg. I have pretty much ruled out the carb since I have been working with Holley (for about 3 weeks) and finally...Jul 26, 2020 · Owner of a 2001 ford f150 4.2 replaced iac & tps still having idle issues upon starting idles ok 2 min. Later hear throttle butterfly open and close idles eradically up & down after it warms up it runs good until the truck is turned off then the problem persists. On steep hills our 1406 will run out of fuel, there is no black smoke at all. We have to back it down and let the bowls fill back up and then go up real fast. At cruse it is lean off the scale of the gage. I adjisted the idle mixture screws to richen it up at idle per the reading on the gage as a lean condition will caulse a stumble per the book.Makes idle in park around 1700 rpms. In 4low with idle adjusted up, truck still stalls when dropped in gear, unless throttle finesse is applied. 2) Still runs rich at idle according to checking the plugs after being brought up to temp. The only good thing is that the truck runs pretty darn good once warmed up, off idle. roasting 42's.Discussion Starter · #1 · May 2, 2002 I've got an '88 TBI 350/SM465 combo in my CJ7. The prom on it is from an '88 Blazer with the TBI350/SM465 combo. The motor runs great at idle and revs freely but stumbles just off idle. The EGR valve was replaced and there was no change. There is also a new O2 sensor on it. It doesn't show any codes.What was the cause of the stumble engine? Why does my TBI hesitate on the injector? When does a 1995 Chevy K 1500 350 TBI hesitate? How to solve engine hesitation and stumble problems? What causes engine hesitation and stumble problems on the 90 +? What causes the idle speed to go up or down? Why is my car running rough with no power?Jeep idles high when started, goes down to normal idle, and once warmed up will idle rough and low, 600-700. Idling will not cause her to die though, only movement and shifting. Jeep will not start back up once shes been running or after she stalls unless she sits for 10-15 minutes, and she will start fine but a little rough.