My '02 5.9L is running rich, I think. I have no messages except for the O2 sensor message that I have had for three to five years, I've replaced all three sensors and still have a message on the third or past the converter sensor. I have had the engine rebuilt stock( the mechanic said he put a hotter cam in it but produced no receipt or literature so I think he BSed me), I have a K&N, I replaced the converter and I have a Flowmaster 44 series muffler with all the stock plumbing. what I've noticed is since putting the Flowmaster on the exhaust has smelled different. It's been four years now since I put it on so there is no reason for it to smell different now cause the new has to be burnt off. I never thought of this until an older mopar nut told me they thought I was running rich. Just wanted to know if anyone else has this problem.