Gunshot backfire?????

I have a 96 with a 5.5 RE and 33s i put a fram airhog filter and for the exaust i put no cat to a dynomax muff, the rear o2 is disconected. lately when i floor it and hit tthe rev limit 5250 rpm at the motor slows to 2-3k it give a gunshot pop. and i do smell alot of gas. I know i burn rich but i get a frikin fireball its looks and sounds cool doesnt bother me but am i having an issue or what. the other day the truck started to sputter and drop to almost 200 rpm and come back up to norm. This happend when i stopped at a light after downshifting a little. i would them smeel gas alot. it never died but comed close what could this be thanx guys

with a disco'd o2 youre probably wasting fuel and your ecu isnt able to fine tune your timing advance and a/f ratio, this is alright till you find out the hard way that your fuel tank has a leak.

so the back fire is because im burning rich? and wat about a leak in my fuel tank?

The second O2 doesn't control fuel mixture, it only checks the effiency of the cat converter.

You've probably got a check engine light though.

The "back fire" you mentioned after releasing the pedal after flooring it could be a cracked exhaust manifold.

Very common for the 4.0's prior for 2000.....

Search "cracked manifold."