Rough idle, sits around 1500 and will drop and rise a few hundred rpm as i sit. If i turn on the AC it begins to rise and drop to near 2000, and 1000 rpm also causes the check engine light to come on. heater doesn't work as well.

runs fine as i drive, tho the AC puts a strain on the power supply so i usually just leave it off, also due to the temp check engine light it makes pop up.

Would this be caused by my IAC? any feedback would be helpful.

Also i was having some trouble with HC, my first smog put me at 109, after replacing spark plugs, spark plug wires, oil, and oil filter it came out to about 63, so i was just short of passing here in CA. Could the idle problem be affecting the HC in any way?