1990 Pontiac GP idle problem

[durrel]

I have a 90 gp. Every time I start the car it idles up to 3 grand (not good shift into drive @ 3000 rpm). The tps, o2 sensor, iac valve have all been replaced. I dont understand what the problem could be. thanks

[richtazz]

check for vacuum leaks. On the top of the throttle body there is an oblong rubber grommet with 3 hard plastic lines coming from it that crack due to getting brittle with age. One feeds the pcv, one goes to the hvac unit, and the other to the emissions canister. A vacuum leak there would cause your high idle.

[reny]

My 95 does the same thing. I changed the OS and Air Idle Control Valve. I'm going to check for the leaks too. Thanks!