No acrchives!! Help...... I have a 2002 T/A with LTs and keep throwing these does after new O2s and all. I have read about exhaust leaks nearby causing these codes as well. The car runs rich as hell and where the header collector and cat back hook up is a band clamp and split pipe to squeeze together with clamp. I can see carbon or soot coming out about 3 inches from these band clamps and they won't tighten anymore. The O2s are only 2 inches from this soot. Could they be causing these codes? The soot also travels backwards? somehow against the exhaust flow and creeps out of this split? Please help me!!

 

Yes sir exhaust leaks near the o2 will kill ya. I just dealt with all of this on my Vette.. Gotta fix those leaks bro..

 

You can try putting in high temp silicone in on the band before you tighten it down, sometimes that will help seal it all up.