GT6ixer

Yeah. It doesn't effect the car at all. Just sounds manlier.

Lizard928

Nate, I am just seeing this thread now. Haven't had time to be on here much lately.

The earlier cars like yours, I have seen a number of them where the downpipe from the exhaust manifold to the catalytic converter fails. But you cannot see it because it is covered by a heat shield that is welded overtop.
This is normally the passenger side one that breaks first. Seen 3 of them so far, all the same year as yours.

Might be worthwhile undoing the cats from the manifold, lowering the exhaust slightly, and seeing how solid those pipes are. You should not be able to move them at all.

GT6ixer

Thanks Colin. I'm sure you got your hands full of diapers these days.

That night I was able to get an inspection mirror between the down pipe and heat shield and didn't come across any holes. I wasn't able to see every square inch of the upper side of those pipes that way so it's still possible that's the culprit.

Wisconsin Joe

Can you put some sort of plug into the exhaust pipe and put a smallish amount of air up the exhaust?

I'm going to guess that the backfire opened up a seam somewhere. You may not be able to see it, but you should be able to hear or feel air escaping.