2003 alero gl idle problem

so recently i've been experiencing a problem with my alero. When i'm in drive and am stopped at a light, my rpm gauge flucuates from 700 to 500 and back up again. I have this problem only when the air is on or the recirrulator is on. when the vent is on without the air, the car is fine. Also when I'm in park, foot on the brake and shift to reverse, and start to go, before i push the gas, the car does the same thing with the idle. Then once i shift from reverse to drive (foot on the brake) and start to go, it again does the idle thing. I have the 2.2L engine if that helps.

If any one has any idea of what is going on, please let me know.

This has been going on for a few months now.

I'd try fuel injector cleaner for a couple tanks first. Then, if that doesn't work, change the spark plugs (and wires if they've never been changed).
If that doesn't work, get a product called Seafoam at Autozone. It cleans the intake manifold, valves, throttle body and everything up there. I've used it myself (I have the 3.4) and it works good.

It sounds like the IAC, probly full of carbon not allowing it to idle correctly.
It can be removed and cleaned out a little to see if it helps.
Try this here, its for the N-body in general..
http://www.automotiveforums.com/vbulletin/showthread.php?t=663849

hope that helps.

we had tryed the fuel injector cleaner, nothing really changed. I'll let my dad know the other suggestions thanks all!