I'm little lost, not sure exactly how to describe it. When I'm driving the rpm's fluctuate even when I'm not accelerating and maintaining the same pressure on the accelerator. It only seems to do this with the A/C on if I turn off the A/C everything seems fine. I went around the block in drive with my foot off the accelerator and it ran smooth with a/c off, with a/c on it would shake (almost stalling) then surge, and then come back down, then a minute later repeat the process. This is an '97 ex coupe automatic. Any suggestions of where to start or what might be causing this? Thanks

 

When the A/C is turned ON, the ECU increases the idle speed to compensate for the higher engine load. Here's how to troubleshoot this control circuit:

 

I had the same exact problem last year and it turned out to be a problem with my IACV.