Alright so here's the deal new to the diesel scene however still know most of the basics. i have a 2003 quad cab 2500hd with 5.9l turbo diesel, the truck has 1 ton running gear and suspension, 4 speed auto trans, 2.5 leveling kit in front, 4" turbo back to 6" bull haulers, and 285/70R17 Toyo open countrys. Just changed the fuel filter and lift pump, recently done trans flush, oil change, and coolant flush. Right now I am averaging 13 mpg. I have been told that these generally get 17mpg. Any and all info would be appreciated tips, ideas, upgrades. please help!!!!