I just got back from the muffler shop.
They replaced my cat with a high-flow one, the guy said that the popping when decelerating will kill the cat just like the old one.
He said something about air valves and air injected emission heads. Does anybody know what I should be looking for under the hood?
1996 1/2 ton 5.2L 4X4 5 speed 3" Rancho lift 85,000 mi cold air intake, headers, flowmaster muffler,
under-drive pulleys, excel coil, new plugs, wires, cap, and rotor

 

with that exhaust being wide open like that i would imagine it is due to lack of backpressure..

 

exhaust popping or crackling is due to an unrestrictive exhaust path whereas unused gas is burned up within the exhaust system.

 

that too :P lol, my dirtbike does it sooo bad when decel.

 

Shouldn't the unused gas be burnt in the new cat ?

 

usually its ALOT more prevailent when you add an aftermarket catback because the mufflers are much less restrictive and you can hear the gasses being burnt up by the cat where those noises are muffled moreso by a restrictive (factory) muffler.

My 04 Cobra made ALOT of popping and crackling during decel after I added a catback and still had my cats...when I took out the cats...the popping went almost away or at least 70%.

I LOVE the crackling sounds though personally.

 

It could just be a small exhaust leak where the new stuff was installed.

 

gasses being burnt up in the exhaust?

seriously?

its the same thing as the jake brake on a desiel big rig...

the engine compression is whats slowing down the truck when you let off the gas... and with the motor reving at hgher rpms without giving it throttle,,, the exhaust sound changes from a steady flow of burnt exhaust gasses to an irratic poppin noise

 

Typically (but not 100%) popping on DEceleration indicates a leak somewhere in the system, something not sealed right and sucking in air that feeds the heat and unburnt fuel which then ignites,,,hence the popping.

 

I think it is just the un-restrictiveness of the exhaust haha if thats even a word...because i have a 65' Pontiac, straight piped and it crackles like no other haha and i have a bronco with 2 cats for some reason...and no muffler, and it crackles pretty good, and my Ram 1500 just has an aftermarket muffler and it crackles somewhat... and of course when it was stock, it didnt crackle at all. Im nowhere near being an expert, but i would guess it has to do with the restriction.