Potential electrical problem causing sparks along exhaust pipe?

Thanks, we will, the only thing is, we are talking sparks way towards the middle - to the back on the exhaust pipe. All wiring would be up at the front. Any particular area that you can suggest as a starting point? It's really weird!

Are you sure it is an electrical spark and not sparks from hot gas leaking out of a small hole in the exhaust pipe?

Car was being worked on all day, so it was cold. Only started it up to be sure exhaust was no longer loud. Only reason we even saw it is because we were down on the ground looking underneath it. Basically there is a heat shield between the pipe and the gas tank. When car is started, the shake of it starting is enough that the pipe makes a brief contact with the heat shield, this is when the spark occurs. Once running it goes away because contact is no longer being made we assume. It's a white spark if that helps. This area is past the middle but before the rear axle.

Your exhaust system may be building up a static charge that arcs to the nearest metal contact. Try grounding the exhaust pipe with a piece of wire and then observe that spot again. If there is no spark then it confirms my guess. I can't think of any harm this would cause though.

I had that thought as well, we will give it a try tonight and let you know!

One more question - we sealed the pipe with jb weld, which in hindsight we should not have used because it wont hold up to temperature - ever heard of that causing static? Again, sparks are not any where the fix was.