I am repeating here what Dave Buschur wrote a few years ago so I hope I have it right:

Dave had his DSM on the dyno when he saw he had suddenly lost 20 horse power. Upon investigating he discovered the AC was on. I doubt that there was anything wrong with Dave's AC.

 

Same here, gotta drive windows down because any time I decide to use A/C, it has to be while im on a long road with no stops or on highway, otherwise, every time I have to stop and start moving again, rpm drop nearly causes me to stall.

 

same thing here with my 03.... sucks!

 

I had this issue as well, only after a new set of cams. First I had the idle value reflashed a tad bit higher, but it would still stall sometimes. A small turn on the idle screw on the throttle body might help. I resolved my issues with my SAFCII, by a small tweak on the low throttle setting.

 

yeah when I turn my a/c on at a stop, my car shakes like its on crack or something. hahahz sometimes worse than others. I guess the boost does get to it and its the car getting of the high. (that was a joke) but also i noticed this happens more to the ix's w/tune as compared to viii's w/tune can someone chime in on this?

 

I'm pretty sure if you're tuned on a standalone ECU then you should be fine.