Mechanics

CHEVY C1500 SURGING AT IDLE

1990 Chevrolet Truck

My 1990 c1500 2wd 5.7L TBI recently began to surge at idle from time to time, never stalls, the problem has gotten to where it will definately start doing it if you let it idle for a few minutes, I cleaned the throttlebody making sure that IAC solenoid is working, its not egr, tps or map, no trouble codes in the ecu. Good vacuum. Some previous owner removed the cap that usually covers the idle adjuster on the throttle body. I just purchased truck started doing this days after purchase, so im assuming they messed w/ the adjuster which in my mind is a no-no for a TBI. It seems like the comp is trying to compensate for something it doesnt like by using the IAC to adjust the idle. Any ideas im pulling my hair out
Avatar
Boredom
August 11, 2007.




Check out the related content below while we wait for the question to be answered by a professional mechanic.


AD