The throttle hang fix cured this problem for me. If you have a V6 it is worth a try. It would also be wise to confirm that the throttle body and idle air control valve are clean. See Ray McNary's write up in the FAX to learn about the throttle hand fix. Of course I'm assuming that the air is working properly and that you are not having the A/C clutch cycling frequently due to low refrigerant or a bad pressure switch.
