Re: 04 Mustang stall when ac is on..Help!
In agreement with Bert. You've paid money for service and it sounds like either incompetence or stringing you along. Unfortunately, without a list of what codes you might have, it's kind of difficult to help you. If you can't get resolution from the dealer, get it scanned (O'Reilly's, Autozone, and Advanced will scan for free), and if you can, get fuel pressure, vacuum, voltage output, and (big if here), running pressures on your AC.
Chewing on asphalt and drinking dinosaur wine