Car stumbles when driving
Le Mans Master
Joined: Jun 2001
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From: Less Talk, More WOT | Houston TX
Re: Car stumbles when driving (rats87)
also it could be your egr valve or your fuel pressure regulator (mine was leaking causing the same symtoms.....just make sure you dont let the shop fool you and say its the injectors and its $2000 like they did me.
Pro
Joined: Jun 2000
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From: Crystal Lake, IL USA
Re: Car stumbles when driving (vettes rule)
I agree on the FP regulator. Easy enough to pull the vac line and check that out. I had raw gas pooling in the plenum but the computer would still compensate enough to run OK now and then.
Also sounds like the cat con could be blocked or partially plugged up or beginning to build significant back pressure. A bit more involved to check out, though.
Also sounds like the cat con could be blocked or partially plugged up or beginning to build significant back pressure. A bit more involved to check out, though.
Le Mans Master
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From: Less Talk, More WOT | Houston TX
Re: Car stumbles when driving (Hendej)
I agree on the FP regulator. Easy enough to pull the vac line and check that out. I had raw gas pooling in the plenum but the computer would still compensate enough to run OK now and then.
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Re: Car stumbles when driving (C4Fetish)
How do I check all these things? Sorry, this is my first car
Le Mans Master
Joined: Jun 2001
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From: Less Talk, More WOT | Houston TX
Re: Car stumbles when driving (vettes rule)
the vacuum hose will be a black tube running off the front of your fuel pressure regulator.....just grab hold of it and pull it off. shouldnt be any fluids at all, check for a gas smell.....then get a friend to turn your car to run but dont start it while you see if fuel comes out of the vacuum line. if it does it means you have a leak in the membrane of your fuel presure regulator, which is an easy fix.let me know if thats what it is and ill tell you how to do it.
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Re: Car stumbles when driving (vettes rule)
I had to shift to neutral, and keep my foot on the gas to keep it from stalling at stop lights. If I touch the bodies of the fuel injectors, the one closest to the front on the passenger side is very weak. Could that alone be causing it?
Im going to check what C4fetish told me right now.
[Modified by vettes rule, 5:43 PM 5/26/2002]
Im going to check what C4fetish told me right now.
[Modified by vettes rule, 5:43 PM 5/26/2002]
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Re: Car stumbles when driving (vettes rule)
I just put on a new fuel pressure regulator, still stumbles. The cap, rotor, plugs, and wires all look fine. I also changed the fuel filter, didn't help. What else?
Also, it only cuts out at stop lights now. It seems fine if I accelerate
[Modified by vettes rule, 8:45 PM 5/26/2002]
Also, it only cuts out at stop lights now. It seems fine if I accelerate
[Modified by vettes rule, 8:45 PM 5/26/2002]
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Re: Car stumbles when driving (ittlfly)
Where is the IAC and how do I check it?
There is a slight smell of gas in the engine bay after it has been run.
There is a slight smell of gas in the engine bay after it has been run.
Melting Slicks
Joined: Oct 2000
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From: Sweden/Stockholm
Re: Car stumbles when driving (vettes rule)
The IAC is on the TB, just under the TPS. Unscrew the TB, its 4 screws. You dont need to get the water lines off the TB, but the vaccume lines from the PVC/EGR must go. Then tilt the TB so you can disconnect the cabel going in to the IAC, then just unscrew it. Put the new one in and set the "minimum idle speed" as posted here https://www.corvetteforum.com/techti...=55&TopicID=2. Now your done.. I hade the same probleme, my car died when I stoped at a redlight. If you can hold a steady IDLE with your foot on the gas pad, and if it dies when you realse it , you DONT have a fuel probleme, you have a IAC probleme.
good luck..
:cheers:
good luck..
:cheers:
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Re: Car stumbles when driving (devilfish)
Will I need a new gasket for anything? Will Pep Boys or Autozone have all of the parts?
Melting Slicks
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From: Sweden/Stockholm
Re: Car stumbles when driving (vettes rule)
you will get a new gasget with the new IAC unit... And DONT break the TB gasget! Or you will have to buy a new one :)
I think you have to turn to GM for the parts. The IAC is "unik" for the TPI desgin
I think you have to turn to GM for the parts. The IAC is "unik" for the TPI desgin
Intermediate
Joined: Apr 2002
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From: Silverdale WA
Re: Car stumbles when driving (vettes rule)
usually the IAC valve will come with a new gasket, however if you take the TB off of the plenum, you may want to replace the gasket unless it is in excellent condition. The IAC should be available through almost any parts store. Borg Warner, Echlin (NAPA) all make them...just depends on how picky you are about original equipment. This is usually a good time to completely clean the TB. The gasket kit should be around $25 from GM and the IAC valve around $70 from anyone. Take the TB off and get a can of carborator cleaner because the new valve will be no good if the valve cavity is covered in carbon deposits. Make sure you take the TPS off...you don't want to soak that with cleaner. If you do take the TPS off...now you have to use a multimeter to make sure you have it adjusted correctly when you put it back on.
***Honestly what I think you should do...buy a Service manual from Helms. I wish I had bought mine sooner...about $2000 ago. They cost $90 but may save you thousands... http://www.helminc.com
***Honestly what I think you should do...buy a Service manual from Helms. I wish I had bought mine sooner...about $2000 ago. They cost $90 but may save you thousands... http://www.helminc.com
Melting Slicks
Joined: May 2000
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Re: Car stumbles when driving (devilfish)
I just had problems you describe. it was the IAC. 2 days after I fixed it by changing the IAC I also had part of the problems you do, stumble etc. but no stalling. This time it was ignition wires, 2 had burned touching the EGR tube.
> I think you have to turn to GM for the parts. The IAC is "unik" for the TPI desgin
Nope, I just bought an aftermarket IAC valve from a parts store. The brand was Standard and it only cost about 1/3 of the GM original. Works just fine.
and secondly, you don't need to take the TB off to get the IAC off. You need to unplug the water and air hoses on the passenger side of TB to clear the IAC. It also helps if you take the TPS off (2 torx screws). Then you need a socket, if it has thin walls it helps. Unscrew the IAC and install the new one. Check the correct torque from shop manual or installation instructions (i think it was 18NM - don't know what that is in lbf).
You can clean a IAC but there is a risk that it brokes when you do that, mine did and I used very mild electronics cleaner.
Good luck.
ToniH
> I think you have to turn to GM for the parts. The IAC is "unik" for the TPI desgin
Nope, I just bought an aftermarket IAC valve from a parts store. The brand was Standard and it only cost about 1/3 of the GM original. Works just fine.
and secondly, you don't need to take the TB off to get the IAC off. You need to unplug the water and air hoses on the passenger side of TB to clear the IAC. It also helps if you take the TPS off (2 torx screws). Then you need a socket, if it has thin walls it helps. Unscrew the IAC and install the new one. Check the correct torque from shop manual or installation instructions (i think it was 18NM - don't know what that is in lbf).
You can clean a IAC but there is a risk that it brokes when you do that, mine did and I used very mild electronics cleaner.
Good luck.
ToniH
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Re: Car stumbles when driving (ToniH)
The end of the IAC, I think it's the pentel, of the new one is a bit shorter than the old one. Is it ok? It still fits in there, but just a bit shorter.
Melting Slicks
Joined: May 2000
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Re: Car stumbles when driving (vettes rule)
Its not shorter, it moves in and out.
Don't touch it unless it is longer than the limit in the installation instructions. Its probably ok if its new.
You need to reset it when its installed. I think it was: start engine, let run 5 sec. Turn off, wait 10 sec, start again. Can anybody verify this?
ToniH
[Modified by ToniH, 11:32 PM 5/28/2002]
Don't touch it unless it is longer than the limit in the installation instructions. Its probably ok if its new.
You need to reset it when its installed. I think it was: start engine, let run 5 sec. Turn off, wait 10 sec, start again. Can anybody verify this?
ToniH
[Modified by ToniH, 11:32 PM 5/28/2002]