2002 Buick Regal's engine would intermittently shut off while driving. If you were driving approximately 30 mph or faster the engine would restart by itself. You just experienced a sudden complete loss of power for about a sec. Scary but still operational. If you were idling and driving slow or stopped, it just cut off and you had to stop and shift to park and re-crank the vehicle. Dangerous, embarrassing, and very annoying to the people behind you.