every once in a while my buick won't start. it will crank like crazy but not start. mechanic has narrowed it down to most likely either a crank position sensor or failing fuel pump. I don't think it's ever happened when the car was cold, it usually happens after it's been running for a while and i run into a store or something. after a few minutes of sitting there, the car will fire right up. car runs fine, no stalling, runs strong.
any thoughts on which one it could be? thanks for any help.