I stuck the air dog 2 with reg only truck a few weeks and I just started really keeping up with the mpgs recently just to see what I was gettin, I live 4 miles from my work and about 5 miles from town so mpgs really didn't matter to me anyway but I started keeping up with it just for the heck of it, but anyway last full tank of diesel I put in I ran about 415 miles on then the air dog stating sounding like it was gasping for fuel so I figured that up it was around 15 or so mpgs.... Does that sound about right with city driving? I have a good bit of performance stuff done to mine as u can see from my sig but wanted to know if u guys thought that we pretty good or not, also what size tank is on a 6.0 anyway? 29 gallon? I usually put about Half a bottle of cetane booster each fill up too, I got 33s mud graps on my truck as well so that's prolly about as good as I'm gonna get but wanted to see what you guys were averaging?