The wife's 2002 sunfire's a/c started acting funny today. For a while it had the surging when at a stop light with the a/c on. I didn't know about it until wednesday. So this morning I pop in a brand new iac and clean the tb. We go to a picnic about an hour away. Everything seems fine. A couple of studders but nothing too bad as I didn't reset the computer. It seemed to idle fine at stop lights. We leave to go home and we get about 15 minutes into it and the A/C stops blowing cold air. We were on the interstate so when I'd let my foot off the accelerator and coast, the a/c would kick in and blow ice cold air. Let's put it this way. It was a long hot ride home. Of course it's my fault that it's acting this way. I get it home and check the a/c pressure and it's ok. I re-check the new iac. The install looks right. As it sits in the garage, it's blowing cold air. When you come to a stop light it blows cold until you stop, then it gets warm again. Once you leave the light, it studders a little and you can hear the fan slow. It's got me stumped.

Any suggestions?

Anybody? could it be a pressure switch that's not working? the clutches going bad?