I am by no means indicating that this is definitely the cause, but this is similar to how my wiring harness issue first started with my Mystique. Since the wiring coatings were cracked, the water would get into the wires and cause short circuits. The only thing is, did the car grind to a halt, or did your engine just stop working, quite as could be, so that you don't even notice until you hit the gas petal? The former probably indicates some type of mechanical failure, while the latter indicates some type of electrical issue, which is how my wiring harness issue first showed signs. I do not even know how to really test for this, but I wanted to let you know. If your car has less than 100K, I would have the stealership take a look at it and replace under Ford's extended warranty. Be very careful, however, as this is a very time consumming task that mechanics do not get paid much to complete and therefore do not like doing, which often means very sloppy work. HTH!