My 03 is only 14 months old and I've already put 140,000 miles on it. Every week it sees about 3,500 miles of highway and gets new oil,oil filter, and fuel filter. My "problem" started about 3 months ago. I pull on average 25,000 lbs a load with my truck and going down the road there is no smoke but when the engine comes back down to an idle the cloud coming out of the exhaust will choke you... not to mention the tears that stream down your face from the burning your eyes feel. It's almost like unburned fuel, VERY RICH. The smoke is white but it doesn't lose water and has never lost a drop of oil. I'm not too very concerned about it because pulling 25,000 lbs it still gets anywhere from 9-11 mpg... . the truck by itself gets 21mpg on the highway. Has anyone else experienced this problem?