I read the OP and chuckled a little. Had a car of mine do exactly the same thing. Took us weeks to figure it out. It would randomly fail to start and act as if the battery was dead. Took it in to the shop. They checked the battery and it passed with flying colors. Then two or three days later it would refuse to start, an hour later and it would be fine. Finally one day at a gas station it would not start no matter how I held my face and so - had it towed to the shop. At the shop they unloaded the car and it started right away. At this point we were all scratching our head.
They drove the car into the bay, shut it off, and it wouldn't start again. Tested the battery again and this time (finally) it showed up as being dead. Pulled the battery and put it in the bench and it tested fine... Shake it a little, it tested dead again... New battery and all was well.
So. Give the OP a break. Weird stuff happens and he asked a honest question. If I owned a vehicle with 800 miles on it and if it acted that way I would prolly be asking the exact same question in the exact same way. Sheesh.
