Bad mpg and power 4.7mpg

[Trey7981]

To start, I've done the egr tune up. All filters and cummins had it on the dyno 2 months ago said it was good to go. I make 20-24psi 70% of the time on flat ground at 65mph. On grade boost is all over the place from 22-32psi depending on rpm. Cac has no leaks. And engine has lost all power and get 4.7mpg from tulsa, ok to minot, nd. Smooth idle no blowby u can see no burnt off oil or coolant. Oh and ultra sonic cleaning of doc, dpf, and scr. Any ideas where to look next