Air filter? Distributor? CAT? Muffler? Crappy fuel? There are more, but these would be a few to look at. I have a 93 accord and once in a great while when its hotter than hell here in florida. After turning the car off, it won't start for 2 or 3 minutes. I can't fgure it out cause it don't happen often enough. I'm pretty sure the heat had something to du with it.