I'm hoping that someone wouldn't mind taking a crack at the problems I'm having with my automatic 2002 Honda Civic EX. Originally, all I knew was that on warm/hot days, while driving, the RPM's would jump up, and my check engine light would come on, but then regulate itself and go back to normal. If it didn't go back to normal, the RPM's would drop to 0, temp gauge would drop to cold, and the check engine light would stay on.(Limp Home Mode??) I'd pull over, and my car would restart with no problems. Same thing happens multiple times before I make it home. No codes are being thrown at all, so mechanics haven't really been able to help me since it's intermittent. I was told that it could be the ignition switch. We replaced it, but that didn't fix it. We were looking around online and in the book for the car, and I've seen that it could be the Main Relay. We aren't very clear if the Main Relay and the PGM-FI Relays are the same things?? We took apart the glove box bracket, and heard clicks from the two PGM-FI Relays as the check engine light was going on and off. We replaced those, but it is still happening. We are assuming it has something to do with Fuel system or Delivery system, but don't really know where to go from here? I would greatly appreciate any feedback???