mine did that too a couple of time exactly as you described it. I had driven it about 15min with the air-con on and made a brief stop. Started the car 10min later and the engine kept trying to stall, got it onto the road and drove it normally and it was fine. Since then I have made sure the the air-con is off when starting the car, then i turn it on 100m down the road when everything is happy. I'm guessing the engine doesn't like the strain of air-con when starting hot. Someone else should have a better answer tho.
1992 Ford Falcon EB2 GLi sedan I6 A4
Fairmont dash, Pioneer DEH-P5550MP, Trip Computer, XH Snorkel, EL Thermo Fans