I use to get a large amount of carbon buildup on the exhaust tips (09 MCSA) until I started using only non-ethanol gas about a year ago. I also put techron in every third fillup.I'm no mechanic and perhaps those of you who are can comment on this, but it seems to me if you get carbon buildup on the exhaust tips then its also building up in the engine and its probably due to the 10% ethanol in the gasoline.

 

They all run rich, could that be it? I just clean mine every day that it

is driven.

 

Mine has done this since mile 11.

 

I don't know if thats the cause as mine hasn't done it since I switched to ethanol free gas and began using techron every third fillup.