This problem keeps me from driving this vehicle. I'm scared I will get stranded.

Each time this car has this problem, it is towed to the garage. Once at the garage, the mechanics cannot diagnose the problem because all of a sudden, the car starts and runs well. This has happened 5 times. It could be electrical, mechanical, or something to do with the gas line. The dealership cannot pinpoint the problem because the problem always goes away when the car is towed or is left to sit for a few days.