A couple of weeks ago my car started high idling to about 3000. It would also spike between shifts (on an automatic). I replaced the idle air control valve, cleaned out the throttle body and had recently replaced the spark plugs. There are no vacuum leaks and I got it back to roughly normal rpms. about 1000 to 1100 at idle and 1600 between shifts or when going from drive to park. Now I am seeing a correlation between the high rpms and running the a/c. The first time it started spiking, I had been running the a/con high for a good amount of time. Recently it started spiking and I found out the a/c had been run. Has anyone else seen this or had this happen? I disconnected the battery and that brings it back down, is there a sensor in the a/c that is telling the system to run high?Any insight is appreciated. Edited by: wanderingjoe72

 

Check for a vacuum leak at the CCP solenoid at the back of the engine.

It would also help to mention the year and model of your S-Series.

 

Thanks. I will check for the CCP solenoid.


As for the other part, this in on a 1999 SL2. Thanks.

 

it could be the throttle position sensor its on the back of the throttle body my car would idle at 2000 rpm wen in nuetral (manual) i replaced the sensor it took care of the problem

 

Concur on the Throttle Position Sensor (TPS). I had the same symptoms as you, minus the A/C situation. Try replacing the TPS (I think less than $20 bucks) and see f that fixes the problem.

 

To WanderingJoe72 ...

To answer your question - Yes, there is a signal that goes through the computer box that will boost the idle RPM when you are running the A/C, but I do not think that is your problem. While the possibility of a vacuum leak cannot be ignored, I kinda suspect that Qwiksl1 and Alaska-Saturn have the problem pinpointed ...