bad idle, bad timing, needs tune up , etc.
need more info but try adjusting the fast idle up a little
the inlet manifold could Be leaking so check the gaskets or the injector seals
Replace your idle air control valve
When the ac is running the idle should be raised to compensate for the extra load. If the idle isn't rising then the car will cut off.
Becaue if it didn't idle, then it would not be running.
Excess load = the idle RPM falls to low and the engine shuts off.
The braking system makes a car stop.
because all vehicles have an idle. Without an idle your car would not stay running.
car run good but has a little vibration idle or running
Check for damaged or inoperative idle control valve assembly.
Fast idle motor is not working. This is allowing the idle to fall below the threshold of what it should be when the A/C is on.