IF I set the cruise control on 60 MPH, might get 15MPG. I have a friend who has basically the same truck, with Smog crap deleted, He is an Native American, living on the reservation. He is exempt from "white mans laws" His words. 28 MPG all day long. And no issues. He told me he got 32 going normal speeds!!
also, with certain tuners, you can shut that DPF system down. It wont hurt the engine at all. Only catch is you must have the right tuner and keep it so you can toggle it back on for emissions testing if required.
