Problem with 05 yesterday i was hooked to my tralior about 17000 pulling a very slight grade the sound of the truck changed to like a 350 gas motor with glass packs or a helicopter with a bunch of white smoke out of the tail pipe. Truck still runs but at about 650 rpms real ruff with lost of white smoke. I have had truck to the shop scan tool picks up one code low fuel but that is from my fass being hooked up and that fuse unhooked there is no water in oil no oil in water tank no external leaks getting ready to pull valve cover and check for a broke rocker arm . Any more suggestions would be great.