Exactly... it's the air injection meeting up with unburned fuel from the combustion chamber. It's the air injection doing it's job. The system is there to give complete combustion a "second chance" and to help emissions.

You'll notice that if you fatten up your fueling, it'll actually stop the popping. The mixture in the manifold is too rich for combustion. (Or you can just pull the air system out )

FWIW, my '04 doesn't have it.

 

Yeah My Junk Does The Same Thing.i Have A 40 Slowmaster Too. I Haven't Had Know Probs Wit It.later

 

OK here is what Im wondering! It has done this with 2 seperate tunes from Allen. The tune I had with the 3.42's it did it if I really got on it hard and went up to like 90. Now I have a updated tune for the 4.10's and regardless of how hard I get on it if I go over say 50 it will do it. What im trying to figure out is why is it doing it all the time rather than just if I really got on it? Some say its me running
rich so what exactly do I need to ask Allen? My A/F ratio? What is the easiest way to check for a exhasut leak. I guess they main thing Im trying to figure out is why ha sit just started doing this? I think I might just call my mechanic and let him drive and hear it and get his advise. If its affecting my performance I cant tell but I really dont think that is the case. Could my FIPK2 be having anything to do with this at all?

 

When the motor revs down, the exhaust pops... I've owned 2 different 5.3's, and they both did it.

 

What I am wondering is why does it do it now and not before and Im talking about with the flows!