02 Jetta 1.8T - When A/C on, clunk, powerloss, sometimes stalls

2002 Jetta 1.8T w/tiptronic. 28K. It's been hot and when I have the A?C going, I have been having issues in start/stop driving with engine "clunk" and near stall. Sometimes at initial acceleration, the worst during what seems to be shift to 2nd or 3rd. Does not happen with A/C off.

Another issue that may be unrelated: Turn off car, pull key out, radio stays on. Sometimes clock resets as well as trip odometer. A couple times alarm goes off and also the clock resets as well as the trip odometer.

Have a service appointment in a couple days. 3 out of 4 dealerships are 2 weeks out. Lucky to get in.

Any other people with these experiences. Thanks in advance.