Hey guys I'm asking for help again because this site is the best ever and helped alot in the past. My dads 06 was an over the road trailer hauler and has 550,000 miles on her! go cummins! but now the exhaust smokes and smells of raw fuel. I'm suspecting a stuck open injector because ive got no codes. When I had another injector failure lasy year I had a code and replaced it and all was well. This time around no code. with my laser temp gun the number one cylinder exhaust manifold bank is around 80 degrees cooler than the rest. So my question is: am i on the right track? stuck injector? can i clean it or replace it? and the oil level isn't going up. thanks in advance and I hope you can help! ps anyone know of a smaller micron filter made for these trucks that is stock size and can replace normal fuel filter?