'02 Cavalier- car idle surging w/AC on and trans in drive

hi- my 02 cavalier always idled smoothly with the air conditioning on, now it surges from 600 rpm to about 1000 rpm, constantly while at a stop sign, and you can hear the AC relay clicking on and off. I need to either shut off the ac or put the engine in park to stop this from happening. It also seems to occur well after the engine has warmed up. Thanks for any help! -Tom

hi- my 02 cavalier always idled smoothly with the air conditioning on, now it surges from 600 rpm to about 1000 rpm, constantly while at a stop sign, and you can hear the AC relay clicking on and off. I need to either shut off the ac or put the engine in park to stop this from happening. It also seems to occur well after the engine has warmed up. Thanks for any help! -Tom

Just to let you know I have an 02 cavalier as well and the same thing was happening to me and it took two years of taking it in to have someone actually look at it to realize that my fan wasnt properly connected to my engine properly. they replaced the wires and it has been smooth sailing since. It got to the point that my car was surging regarless if it was in park or not. Spent a ton on gas until they fixed the problem. I would suggest checking the connection from your heater fan to the engine.

Fixed! Thank you jleon134 (http://www.automotiveforums.com/vbulletin/member.php?u=514052) for the advice. There was a bad electrical connector at the A/C temperature sensor. I noticed that the problem got worse when I jiggled the wire leading to that connector. I replaced the connector and problem solved. The part # is 88988301 - it wasn't cheap! $56 at the Chevy dealership. Rockauto.com has it for $31. Thanks again jleon134!

i have an 03' cavalier and it does the same thing, but when i get off of the highway though it idles around 2500 rpm's. do you think that could have been the same problem?