My truck seems to get the best fuel mileage (29+) during the first 200 miles, then drops off after that (21 to 22 for the tank). Scatchin' my head on that one. I fill til nothing more fits in the filler neck.
BTW that is some pretty nice HP numbers!
Why don't you join us...? (Team Cummins)
http://ecomodder.com/forum/team.php?id=24