09 prostar horrible Mpg

[Waterloo]

I'm wondering what the oil pressure is like? Having seen the work my dealership did and hearing your story brings back ugly memories. And I would bump the HP down, unless you are hauling 100,000 lb loads. And like Nick said, a pyro and boost gauge, and never lug the motor, keep the rpm's up. I bet they dry started the motor, that is what my gut tells me by your description of how it was running when you got it out of the shop. The mileage sounds about right though, I get 6 mpg all day long pulling a dry van with a mid roof, no fairing. 18 speed with 3:42 rears. I have a factory 600hp set to 485hp, Rawze did the tune.