My idle speed just will not go down. The IAC valve and TPS has been replaced and I just had it checked for vacuum leaks. I cannot figure out how to get my idle down. I have tried just about everything. I am not getting any error codes and had them checked and none of them relate to this (Only error I had was the cooling fan and that was taken care of).

I bought the car used and don't know too much of the history. Right now the car idles at 1500 and I cannot figure out why it does this. Can someone please throw me some ideas as to why this is happening? I have been trying to fix it for three weeks now and have not come to anything promising.

The car is a V6 and I have posted this on the V6 boards before and have not gotten anything helpful, perhaps maybe some people on this board can help.

91 Camaro RS V6.

 

Just a simple thought, but have you tried backing the idle srew back a little? How about proper installation of TPS and IAC? Those places I would definitely start with.

 

Tried fiddling with the idle screw, in fact when I pull the screw back a bit I noticed the throttle lever does not even touch it. As far as the IAC and TPS, the scanner shows no sign of error and I checked the gaskets on them and they are on properly. I already reset the ECM when putting them in. Like I said im pulling my hair out trying to figure this out.

I should also mention that when I am shifting say I am going from 3rd to second, when I take it out of gear and disengage the clutch, my RPM's rise to 2800 adn stay for a bit until I either put it into gear or slow down with the brakes, its strange. I already had the car checked for vacuum leaks and thats not the problem, any ideas?

 

The lever should be up against the idle screw. With the scanner check the IAC counts (or steps) at idle, if at zero then the IAC can not bring the idle down (zero being fully closed).

Check that the throttle cable is not binding or is too short.

May also be the throttle shaft binding in the TB because of wear.

RBob.

 

I had a real bad problem similar to yours, and after installed the new IAC, I never reset it. As soon as I did, viola. No more idle problems. When I said "Proper Installation", that's what I was talking about. And of course, I guess your TPS is non-adjustable isn't it?

 

Start by adjusting your IAC according to the manual, then if the problem persists check shaft in the throttle body. Had the same problem, shaft wouldnt return to setscrew cause it was bent and bushings in TB were worn causing a vaccuum leak.