Cause it's a hooptie..
Its battery could die and the engine would stop running. Or a cable plug could have been unplugged and the car would stop, the only real reason it would do this is that the car would hit a large bump or halt at a sudden stop.
a car bomb
yes.
Yes it could.
A large enough "EMP" electro magnetic pulse would do it.
faulty ignition switch
bad idle, bad timing, needs tune up , etc.
Your car may stall or stop running after idle because of a problem with its fuel or electrical system.
yes
I would suspect warped rotors.
Keep the key in the ignition, stupid...
Yes.