I was one of the folks who had a "mystery no start problem." Do a search and you will find a couple of excellent threads on the topic. Mine problem escalated to the point where it the engine did cut out on me at stoplight and wouldn't start for about 30 minutes. It's was the fuel control relay (why it happens is covered in the thread) but the part costs about $250 and it can be swapped out in about 5 minutes. Problem will probably be gone.