[396Pwr]

I have an 04 duramax crew/dually/4x4 - I put on an aftermarket exhaust from banks and a K&N aur filter. I have had no problems so far, but I have recently noticed more soot coming from my exhaust that had not been there before. The exhaust has been on from about 30,000 miles and it now has 135,000 miles.

Any ideas on what would start this to happen ? and what I can do to fix it ?

Thanks