why does my car shut off while driving

could be bad crank sensor. check for spark when it does this.

Just to add to this one i would say its most likely a bad ignition module but would do some testing first.The first thing would be to check for spark when it wont start.If there isnt spark then we can check and rule out the crank shaft position sensor by checking it with a multimeter.I should read about 800 ohms when they test bad they will read as a open.