c4 idle problem
Thread Starter
3rd Gear
Joined: Dec 2013
Posts: 3
Likes: 0
c4 idle problem
I have a '94 that won't idle down without tapping the throttle. Once I accelerate the throttle lever will not come back into contact with the idle stop, and therefore, causes the motor to run too fast. If, I tap the accelerator pedal firmly, it will return to normal. I've had it tested and it does not throw a code and the company working on it can't find the problem. If the motor is shut off, the throttle lever will work freely and return to the stop. Idle speed is aprox. 1100. If I tap the throttle it will immediately return to 750rpm. This is a stock LT1 with 86,000. Anyone have experience with this issue. Thanks....vetbet
Drifting
Joined: Mar 2012
Posts: 1,492
Likes: 61
From: New Jersey
Have they checked the TPS (throttle position sensor) and IAC (Idle Air Control valve)? If so, you may have worn throttle blade shaft and/or bushing causing it to bind. If so, before you replace the TB try the following. Pull the throttle body and thoroughly clean it front and back along with the IAC. Then put some light oil or WD40 into the TB blade arms and work them back and forth. Reinstall and see how it works.
Advanced
Joined: Aug 2013
Posts: 71
Likes: 2
From: Oregon
Intermediate
Joined: Sep 2013
Posts: 25
Likes: 0
From: Sanford Florida
Had a similar problem recently. Changed the TPS, checked IAC, the throttle body was clean. Would only happen when I would come to a stop. It would idle about 250 RPMs higher than normal. Would blip the throttle and it would return to normal Idle. Was driving me nuts. Decided to spray some WD40 on the outside throttle body shaft area (both sides) and the problem was resolved. Give it a shot, you never know.
