I finally fixed my A/C after two years of it not working but right away I experience a rough idle when the A/C was on. I clean the IAC and throttle body, they were not that dirty to begin with, and the problem got better but only for a couple of days. The rough idle has come back, sometimes it's better and sometimes it's worse. When I turn the A/C off the car idles fine. What could it be?

 

No one has a clue on what it could be?

 

Do we assume you also cleaned the throttle body? And did you reset the idle with the IAC and the TPS disconnected? Does your idle drop when you turn on the AC? Check them out first and see what happens. The AC compressor puts an extra drag on the motor abut as you know the IAC compensates for the load by increasing the air into the idle circuit.

 

Yes, I cleaned my throttle body. No, I did not reset the idle with the IAC and the TPS disconnected. How do I go about doing this. Yes, the idle drops when I turn on the A/C.

 

If it doesn


Remove and plug the IAC hose from the air inlet duct. Plug the duct hole also. Unplug the TPS and jumper wire 1 to 3 on the connector. Loosen the nut on the throttle linkage at the throttle body. Start the engine , you may need to feather the throttle at the throttle body. Adjust the throttle body linkage so that the engine idles at 500rpm. It should be a steady idle. Lock down the linkage and make sure you did not change the idle. Now you need to reset and adjust the TPS. Put everything back together and start it up. Idle should be at 750 rpm. If different then the IAC may not be adjusting. Also make sure the engine is warm and not running on the cold start circuit. When you turn on the AC the rpm will drop for less then a second until the IAC compensates for the engine load. If it doesn't you may have a bad IAC.

 

Thanks for the help. I will try that when I have a chance and post my results.