Idle Need Help!!!!!!!!!!

[Tech_n]

This issue just happen today and I wanted to know if anyone had this problem.
I was sitting at the light and the RPM fluctuated, then the car turn off.
I started the car again and drove it and I did not have no problem, but it seems like everytime I stop it fluctuate like it is loosing air. Do anyone no what this can be.

I had the same problem with my other car and it was the hose so can someone assist me. I check the same hose but it do not seem to have any cracks. Can someone just tell or show me where all the vacuum hoses are that would cause this problem. Thank You

[Chazman]

Check ALL the vacuum lines - any one could cause this.

But I would also strongly suspect the idle air control valve is dirty.

[Tech_n]

Thanks a whole lot, I am going to try that

[Sigmund1965]

What kind of engine is it? Big issue with the 3.1 and 3.4 is the lower intake manifold gasket. If this is leaking you will notice an idle problem and maybe notice that your coolant level is dropping.

[Tech_n]

It is a 3.8 and the colant level is staying steady.

[Sigmund1965]

Lift the hood and with the engine running listen around the intake manifold, down between the valve covers. See if you can hear a vacuum or sucking sound. The intake has three manifold gaskets, one upper and two lower ( one front and one back) the lower gaskets have a problem with going bad. You can replace these yourself if your somewhat mechanical if not your talking about $300. If anything I would check the Idle Air control and make sure the seat for the IAC is clean ( this area is prone to carbon build up ) also look into the intake butterfly make sure this area is also clean. If you remove the throttle body and clean everything up your talking maybe 3 hours work. the lower manifolds and gaskets add about 2 hours.

[93_R/T_TT_Stealth]

Here is how you clean your IAC i posted this before - but ya prob. didnt need the info then lol
no the IAC (Idle Air Control) valve or the or the IAB (Idle air bypass) -- what the IAC is an electrically-operated valve which allows air to bypass the throttle plate in a fuel injected engine to regulate engine idle speed. And if not working properly it will make your idle go frantic or should i say raise an lower with out compressing the throttle. In this age of fuel injection, idle problems can literally be caused by hundreds of different things. When your car is new the IAC works remarkably well. The problem arises when the car gets some miles on it (usually 75K+) and carbon fouling takes its toll.
What happens is dirt, excess air filter oil, and most notably carbon gunks up the IAC valve and doesn't allow it to either open or close properly. This can cause an really high idle, a lumpy/surging idle or no idle at all. The solution is to either replace or clean the IAC.
you should have no trouble finding yours. They all look basically the same
Removing the IAC:
This part is simple. The IAC has an electrical plug that needs to be disconnected (picture 2 "C") Then all you have to do is remove the two bolts (Picture 2 "A") that hold the IAC to the throttle body or intake. Watch out for the IAC motor to throttle body gasket, don't lose it!

Cleaning:
Next all you do is use the carb cleaner to clean the carbon out of both of the holes (picture 3 "C") in the IAC valve and both of the holes in the intake/throttle body.

Putting it back together:
A self explanatory step. Put the IAC in place and install/tighten the bolts. Make sure you don't forget to reinstall the gasket.
Fire her up!
Finally you need to start the car and let it run for a few minutes to burn any leftover carb cleaner in the intake. You may have to crank the engine a little more than normal to start it for the first time and don't worry about the white puff of smoke you see coming from the exhaust because again it's just the carb cleaner.


Good Luck!
diagram

On A Ecotec Engine
A better look @ it on the throttle body
What it looks like off
what it looks like with the valve an the motor seperated an cleaned




those are 2 posts i made - in the cavalier section
hope the help!

[dreyes78]

I had a fluctuating rpm problem too. And after a couple of weeks it started killing on me. Ended up being the Throttle Position Sensor ($34-45). Worth a shot.

3.1L engine

[kustomkid54]

Tech n
What year and TYPE of car are you running?

[GTP man]

Hello,
I have a GTP 1996 3.4L and got 3 of the wires on the back injectors chewed by mice....yes mice......now after all is repaired, the car is irregular on idle. I mean that instead of beeing quiet at the regular 800-900RPM idle position, it start to shake and lightly accelerates/increases the RPM by itself to 1000RPM where the shaking stops but it goes down again and all starts again, otherwise it works like a charm. I didn't had this problem before having the car scanned for the main problem above which happened all the sudden one morning. The car barely started, the engine was sheking, no power on acceleration, engine light came on and after a day of scanning found the 3 injector wires chewed by damn mice....bloody kritters. Now that the wires are new, I have this IDLE shaking problem.......it is like the engine is late on the comands.....what I mean is the fact that if I get to a stop light....the RPM take a couple of extra seconds to go down to the usual 8-900RPM and there it starts to shake, as well as on NEUTRAL or PARK. Could someone please advice me on what to do? Could it be the IAC? Thank you in advance.

[crazyman1]

I too need help. I have a 98 grand prix with the 3.1 engine. I also have flucuating RPMS at idle it will just start to jump around (search). I have done pretty much everything. Changed IAC today. that was 71 dollars. I have cleaned the intake and still no change. I am in desperate need to fix this because I am selling this car because i purchased another vehicle. When I purchased this car 2 years ago it started doing the same thing. 02 sensors were replace, and now because of the cold weather in winnipeg, I am faced with the same problem. Please help..

[BNaylor]

Originally Posted by crazyman1

I too need help. I have a 98 grand prix with the 3.1 engine. I also have flucuating RPMS at idle it will just start to jump around (search). I have done pretty much everything. Changed IAC today. that was 71 dollars. I have cleaned the intake and still no change. I am in desperate need to fix this because I am selling this car because i purchased another vehicle. When I purchased this car 2 years ago it started doing the same thing. 02 sensors were replace, and now because of the cold weather in winnipeg, I am faced with the same problem. Please help..

crazyman1,

Please check the date of the thread before resurrecting old threads. We prefer that old threads are not raised from the dead since one of the participants in this thread did in fact pass away. I would recommend starting a new thread addressing your issue. This thread has been closed.


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