idle surge/vibration with AC on
with the car in drive (e.g. stopped at a traffic light) and with the AC on, the idle surges by a couple hundred rpm and the car shakes very noticeabley. happens every 5-10 seconds or so. gets worse with the AC cranked up to max. doesn't happen when the AC is off.
what's going on here? Idle control valve? give me some ideas guys. thanks.