Got a problem! Help please
Thread Starter
Pro
Joined: May 2006
Posts: 549
Likes: 2
From: Bardstown ( Bourbon capitol of the world ) KY ( The Bluegrass state )
Got a problem! Help please
When I'm driving and come to a stop my car will stay at a high rpm, around 2grand. The only way to get it to stop is to hit the gas, it dosen't do this all the time, it comes in spurts 
. The car is a 6 speed. Any suggestions.
Thanks J
. The car is a 6 speed. Any suggestions. Thanks J
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
Sounds like your Idle Air Control (IAC) is sticking or dirty.
The IAC is a small motor driven valve mounted to the Throttle Body, just below the intake.
DO NOT attempt to constrict or pull out the plunger -- it may damage the unit.
It can be carefully removed (take care to not damage the o-ring) and its passageways cleaned with a throttle-body cleaner.
After re-install, there is a 'reset' procedure for the IAC -- if you do not have a FSM (factory Service Manual) do a search or post back for the procedure.
The IAC is a small motor driven valve mounted to the Throttle Body, just below the intake.
DO NOT attempt to constrict or pull out the plunger -- it may damage the unit.
It can be carefully removed (take care to not damage the o-ring) and its passageways cleaned with a throttle-body cleaner.
After re-install, there is a 'reset' procedure for the IAC -- if you do not have a FSM (factory Service Manual) do a search or post back for the procedure.
Pro
Joined: Mar 2007
Posts: 594
Likes: 354
From: Mt Prospect IL
2025 C4 of the Year Finalist - Unmodified
One thing to check that may sound crazy but sometimes is overlooked, checking the floor mats. Make sure that nothing is blocking the pedal. Also under the hood, check to make sure that the throttle body is clean inside and out. I have seen dirt on the outside cause a lazy throttle plate return.
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Another possibility is that your butterfly is sticking. Suggest removing your TB and clean thoroughly with TB cleaner. As mentioned, also clean your IAC.
At any rate, it is more than likely your IAC or butterlfly sticking. Easy to check the butterfly in driveway with engine not running. Remove air accordian and manually operate throttle half-moon and observe any sticking or binding when you slowly release throttle to idle. Then open throttle and let go of it so that it "snaps" back quickly to idle. This is essentially what you are doing when you tap the gas peddle to get your idle back.
At any rate, it is more than likely your IAC or butterlfly sticking. Easy to check the butterfly in driveway with engine not running. Remove air accordian and manually operate throttle half-moon and observe any sticking or binding when you slowly release throttle to idle. Then open throttle and let go of it so that it "snaps" back quickly to idle. This is essentially what you are doing when you tap the gas peddle to get your idle back.
Last edited by MikeC4; Mar 6, 2009 at 11:04 AM.
Thread Starter
Pro
Joined: May 2006
Posts: 549
Likes: 2
From: Bardstown ( Bourbon capitol of the world ) KY ( The Bluegrass state )
I'll give it a try!
Thanks guys 
! I don't know much about the IAC, but I do have a book on the lt1. I'll give it a try this weekend, and let you know.
Can throttle sticking also be caused by the valve train?
! I don't know much about the IAC, but I do have a book on the lt1. I'll give it a try this weekend, and let you know. Can throttle sticking also be caused by the valve train?
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
The IAC is a little black gizmo bolted on your TB on the underside. It is a "stepper" motor and comtrolled by the PCM. After you remove TB, remove IAC, spray pintl only with TB or carb cleaner to remove carbon deposits. Do not spray the bulk of the IAC, as this contains the stepper motor. So........hold IAC in one hand with pintle pointing to the ground and then spray the pintle and shaft only...let the carbon mess just drip off. As mentioned by theAdmiral, dont turn the pintle.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Next time the car is stuck at ~2,000 quickly pop the hood and see if you can push the TB linkage back aginst the stop.
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Thread Starter
Pro
Joined: May 2006
Posts: 549
Likes: 2
From: Bardstown ( Bourbon capitol of the world ) KY ( The Bluegrass state )
Thanks guys! Wounder if this could hurt the performance of my car? I know the last time I was at the dyno, 95bluebomber cleaned my mass air flow and it picked up 10rwhp!