2001 cadillac sls pulses when a/c is on

Hello,

My 2001 cadillac sls will pulse up and down @ idle when the a/c is on. It does this constantly, not like when the a/c is engaging and dissengaging. It runs smooth when a/c is off. Thanks ellis479

The pcm is try to stabilize the idle, now as the compressor cycles the idle will vary slightly, if it is a gross change in speed, the throttle bodyand/or isc could be dirty or faulty ( the iac), a full scan may show something or an experienced tech can find out what's what.

Maxwedge,

Thanks for the information. I couldn't figure out why it only fluctuates when the a/c was running. Once again it's not like the clutch cycling, much more rapid. Thank you ellis479

Maxwedge,

I had the throttle body cleaned and the camshaft sensor replaced. This not only fixed the idle problem, but increased the gas milage dramatically. Thanks for your help...........Ellis479

Thanks for posting back results, did a scan show a cam sensor issue?