Rough Idle, Stalling out due to A/C
 

Hello all, I have a 1997 Chevrolet S-10 2.2L that is having some engine problems. When the A/C is turned on, the idle becomes very rough and sometimes stalls at stop lights, stop signs... The engine doesn't die it just loses power and I have to feather the throttle to get it back. When the A/C is off, the engine runs fine. At higher speeds, the engine runs great with the A/C on, just the slight loss of power due to the A/C--this lets me know that the A/C is not the problem (and the fact that the A/C hasn't begun to smoke or burn up). When the A/C is turned on, the engine revs up initially then the RPMs decrease back to normal idle. I know that most vehicles keep the RPMs up while the A/C is on. Could this be due to the throttle positioning sensor not increasing engine RPM? Or is there something else that could be causing this problem? All spark plugs and wires have been recently replaced with AC Delco platinum plugs and high quality wires (I don't know the brand). Also, my A/C is equipped with 134a freon but, I noticed that the compressor does not cycle (turns on but doesn't disengage clutch until A/C is turned off). A/C was replaced with a rebuilt compressor and serviced and charged by a local mechanic. Does anyone have any ideas?

Thanks

RE: Rough Idle, Stalling out due to A/C
 

You possibly could have a cat. issue. Check your air filter and change the fuel filter also. A lot of times the fuel filter can cause engineidle problems. After you have done that, the next thing to check is the upper intake throttle body an PCV valve.

To do this:
Take off the upper intake boot (part on top of the engine)so you can can clearly see the throttle body, check all around the throttle body and intake bootfor oil. If you find oil, replace the PCV valve. The PCV valves go bad sometimes on the 2.2L engines, so its a good thing to check. A bad PCV valve will not let the extra air into the intake manifold to handle incresed engine stress caused by rapid acceleration or compressor loads at idle.

RE: Rough Idle, Stalling out due to A/C
 

Howdy, The Haynes maual pg 4-19 refers the (IAC) Idle Air Control valve it controls the engine idle speed. Most all parts stores carry the manual. DIYers rule
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