I'm stumped....any thoughts?

[Beaver]

Its got 556k. Yes did all of the dpf cleaning and nox sensor checks. Replaced oulet nox and doser injector.
Oil pressure is just over 35psi at 1500rpm.
Rawze, is Mr Hag up here in the Northwest? Contact info? I just want to fix it and run right. I'm a carhauler so we already get terrible mpg and I can't afford to stay down in the 4.8mpg range forever. Plus, it would be nice to learn more about my motor.
Thanks again gentlemen!!