Thanks to Hector Vargas for contributing to this FAQ!
My car wouldn't start at any given time; this happened for a period of two months, Every time I took the car to the mechanic he look at the computer and check the codes... nothing. He changed a different spark plugs (better quality). He checked the gas pump, changed the gas filter... nothing. Longstory "short" Just about the time you loose faith in your car. The problem was registered on the computer and it was the crank-shaft sensor.
Thanks to Nick McShane for contributing to this FAQ!
I had a similar problem with my SAAB 9-5. The car would intermittently stop whilst I was driving (quite dangerous given it was an automatic). Car would generally restart OK, but sometimes required a bit of cranking. Workshop didn't believe me at first until it happened to their Chief Mechanic. Problem was crank-shaft sensor - which had to be replaced.
Pricing for CRANKSHAFT SENSORS (ignition & related)