surging pulsing with AC on

[talldudenumber5]

with the ac on in idle the car pulses and vibrates really bad and driving down the road with the AC the car kind of pulses as you drive down the road. with the AC off there are no noticeable issues

[MyOtherRidesAVette]

I believe there is something that automatically adjusts the rpm to compensate for load, the reason, the engine (when everything is running properly) maintains a constant rpm, regardless. I suppose if this is failing/has failed, the load of the compressor could cause what is happening to happen.

Look at the rpm, at idle, without the a/c on, and then turn it on a see what the rpm does. I suspect it drops considerably, almost to a stall. Perhaps someone can identify what I am referring to and help out here. I quit working on engines when they started using fuel injectors, so most of this electronic $hit is foreign to me, other than what I read and learn.

MORAV