Can I get better fuel mileage

[Fergie]

Figured I'd give an update. Dash gauge is off, but by half a mile. So my first tank actually got 7.7 MPG. Second tank full 8.0 mpg. Both times gauge read half mile a gallon better. Got 373 miles on third tank and it's reading 9.0. So a possible 8.5 mpg. When I bought this I as hoping for 7 considering my current 93 kW t600 with Detroit as getting 5.8. Figured you'd think they'd increase by 1 mile in 19 years. Was pretty disappointed when I only got 5.8 on first tank full. A bit disappointed in brother in law, he's got a couple trucks and does about the same thing I do except he does pull alot of van trailer hauling seed corn. He's got older W900's with cat's, thought showing him this mpg gain he'd want to join in on the money saving. He laughs at the idea of slowing down, oh well I can lead a horse to water but can't make them drink.