ok, whenever my A/C or heat is on, my engine starts revving about 300 RPMs every couple seconds. Whats goin on? also, even if i have set it to off, i still have heat or cold air coming out of the vents near my console. any suggestions on what to do?

 

i think they all do that man

 

Matt,

While this is happening, check the A/C compressor clutch. I'm guessing that the compressor is cycling rapidly due to the relatively low ambient temperature, and the ECM is compensating for the load changes by kicking the IAC up a bit, then reacting to the compressor shutting off by dropping a few RPMs from teh target idle speed. It's all programmed in the PROM, and designed to keep the engine idle speed and quality stable while the A/C compressor cycles.

 

when it revs up, the clutch engages.