[Hersbird]

Your truck may not have the urine injection but it definitely has a DPF and regeneration modes. You need to learn when those are happening and how to limit them, and never interrupt them (or they just immediately start all over again from scratch). That or just get rid of it. The 6.7 can get good mpg even bone stock. TFLtruck has a YouTube video of one doing a empty loop where they get over 20mpg. Then again their Ecodiesel Ram did 33mpg on that loop which is why that's the truck I really want.

Ps, I have a friend with an 2012 and he is only getting 15 but he is going 75. At least he says pulling a horse trailer it only drops to 13. The canopy actually probably hurts aero compared to an open bed or flat cover, steel or fiberglass. The smaller tires also hurt especially with aggressive tread. They increase highway rpm and I bet they are just as wide giving no reduction in frontal aera.