Idle fluctuates when I turn the A/C on

[AirBuick]

My car idles fine when not running the A/C; the minute I turn it on I get surging, almost stalling and just general idle all over the place. Any ideas as to cause? Got good BLM's at idle ~123.
Thanks.

 

[gofstbuick]

Is the IAC properly set? Maybe the IAC is bad or the IAC passage is obstructed.

 

[scottyb]

Check for vac leaks. I had a leak last month, but it ran fine until I turned on the AC. It started to jump a bit.

 

[AirBuick]

Scottyb:

What vacuum leak did you find? Does the increased load on the motor from running A/C flare up a small vac. leak?

 

[scottyb]

It was a vac line. It came loose from the charcoal canister.