I have a 93' pickup with a tiny 22RE. When the the truck is at idle with the AC on , the idle will jump up and down, from 800rpm to 1500rpm. It will rev up and down about 5 times and then settle back to the normal approx. 800 rpm. It will also do this in rush hour traffic while moving about 5mph, only this makes the vehicle lunge forward a bit. It doesn't do it all the time, but it does it a lot. I'm used to working on my landcruisers mainly, so AC controls are not too common in my book. Is there an AC idle control sensor/soleniod/valve that causes this? What else could cause this?
