my car engine turns off at stop light periodically on 1993 Ford Crown Victoria

Above does not occur all the time. But only when car is not moving. When it happens it is not difficult to restart. No rough idling noticed.

Asked by for the 1993 Ford Crown Victoria
You might have an egr valve sticking in the open position,or a vacuum leak.Both are very common on this year of crown vic.Another possibility is the torque converter fault.