I have a 2005 FX4 5.4L, and I got a custom exhaust put on as a thank you gift from a friend a couple of weeks ago. I'm running a flowmaster 40 series SI/DO, with 2.5" piping out back. I've noticed that I have a sooty residue on the bottoms of my tips, and was wondering if I need to get a programmer & see what I can do about getting a custom tune. I've already re-oiled my K&N air filter, and cleaned the MAF sensor a few days afterwards. I haven't had any SES/CEL indications, but I haven't been able to get to autozone to have them pull any codes. Any thoughts in the meantime?

Thanks,

Dave

 

Soot just occurs. Every engine produces it. Nothing you can do about it. Running higher octane will increase it more since the emissions wont be a great but it doesn't matter, wash once or twice a week and its all good.