Crank sensors usually break down over time and can stop the car whilst running it. An example is the car starts fine in the morning you drive 7 or 8 miles to the supermarket and when you come out it wont start. Rev counter does not move when you turn the car over. Leave it half an hopur and it starts again. Ive been to a few jobs where the bloke works 10 miles away and after 9 miles the car breaks down!
Half an hour or so later once the sensor is cool it fires up and away he goes.
