So here's the story, It's a 1986 Camaro Z28 305 with a 700r4.

When I start it up for the first couple of minutes it is fine but then once its starting to warm up it sounds awful. It backfires over and over again like a bad exhaust leak. Then if you rev it up it really sets it off on the way back down to idle. Its like gunshots. This all started one night a few weeks ago, it backfired while driving quite a bit and had a lot of power loss. Then I took it home and parked it and haven't tried to do anything with it until today. Not surprisingly the problem is still there...

Any and all help will be appreciated.

 

Bump for any information on what would cause constant backfiring. Oh one thing I forgot to mention is the previous owner cut off the exhaust and basically welded a flowmaster at the end of the Y pipe and thats it but it hasn't been causing it it backfire until recently. Its been loud and annoying but not running like udder S**t

 

lack of backpressure can cause excessive afterburn, especially when coupled with a timing issue.

Retard your timing a couple degrees, see if that helps. Unfortunately afterburn is a common symptom of a car that had cats no longer having 'em.

Somebody correct me if I'm talking out of my a## here