My car got some very noticeable popping on decel when I swapped in 4" exhaust with a race magnum. Initially, I thought it might be fuel igniting in the exhaust ... However, there was no change in the popping after completely zeroing out all the high vacuum cells used during decel (FAST ecm, verified 0.00ms PW).

 

arizona speed and marine and ya. it pops like a BITCH! but that is probably due to a slight exhaust leak. It still pops, but not near as loud usually. Just an annoyance, really. Im gonna repair my collector gaskets today and I'll report back

 

Why did you dig up a thread from 2004? LOL

 

cause im an idiot and dont look at things like that

 

none, 5" open dp! lol!

 

You can re-cal the PCM to reduce pop @ close-throttle timing advance field. There is a PCM program field for this in the flash file. I did this on my application... (97ss 383-D1 MM6 OBD2). B.

 

Like everyone is saying its either too much or too little fuel or timing.

Lt1s tend to do it with free flowing exhaust, but you should be able to nearly eliminate it with enough tweaking.

I'm running waste spark and had a problem when I had too much fuel on decel, plus exhaust leaks to let in fresh air, and the waste spark fires on the exhaust cycle.

If it helps I have run open dp and now run straight pipe to the axle - both times took some tweaking to tone it down - now its a soft gurgle, but no pop.

 

Open DP here - I like the popping! Sorry, I can't add any usefulness to this post...

 

I have a B&B exhaust (Billy Boat) and i have no popping. I am not sure why no one uses this system, it is good looking and sounds great. (from the muffler back the stainless steel is polished).
The long tube headers that I have (Kooks) with this setup has just added to my performance without any popping!