engine surge when in drive and AC on!!

I have a 2002 Cavalier and when in drive and with the AC on the engine surge. At stoplights it surges when foot is on brake. Can anybody help me with a solution.

surges at a stop light only? sounds like a missfire..

Not a missfire. Just got back from Montreal, and had the same problem. Your A/C presure valve needs to be cleaned/replaced. I had mine cleaned by GM for $80 (CAD) and the car ran great again.