Heater Problem

So anytime I have my heater on, the car will kinda rev up every 10 seconds or so... Its about 1/8th of an RPM(x1000, of course)... It mostly seems like when I'm idling, or coasting... Any ideas to whats going on??

Thanks!!

It's your a/c compressor cycling. It will do it any time you're in a defrost mode (defrost or mix). Completely normal.

So basically floor or panel and it wont do that??

Thanks!! Thats a relief!!

but AC compressor kicks on to dehumidify the air blowing to your windshield, so it won't fog up!!!!

kinda neat idea, huh???

but AC compressor kicks on to dehumidify the air blowing to your windshield, so it won't fog up!!!!

kinda neat idea, huh???

Yeah, but more annoying when car sputters... But i'll live!!

ahh, sputtering when the AC compressor cycles on-off???

then, you'll haveta check vaccuum lines for leaks; idle speed controls for carbon buildup, etc...

Well I shouldn't say sputtering...Like i said when I'm sitting in a drive thru for example.... You can notice the car rev up slightly... When I'm driving its not noticeable, unless i'm coasting.... I've checked and its fine on floor or panel