engine revs up and down when idling, only when A/C is on on 2002 Chevrolet Cavalier

When I'm idling, the car sometimes revs between 500-1000 rpm, over and over again until i start moving. It generally only happens when the A/C is on....

by in Los Angeles, CA on October 04, 2010
2 answers
ANSWER by on October 05, 2010
this may be normal as the idle will kick up when the ac compressor cycles on and off.
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ANSWER by on November 18, 2010
You could have a vacuum leak or the fans are not working. The fuse box in the engine compartment left fender there is a relay for the A/C and one for the heater fan. The one for the A/C controls the fans. Switch the A/C and blower motor relays, turn on A/C, If the fans come on the relay will cost about $10 .