Well, I have just shy of 6000 miles on the new 2013 Columbia glider I bought. Fuel mileage average to date.... 7.52 mpg, pump to pump actual calculation. And definately not on light loads all the time. One last friday was close to a gross load of lead, with a large portion of the run on two lanes, up and down hills all the way. That one came in at 6.7 mpg. Todays fueling came in at 8.81 mpg on 630 miles. That was lighter and primarily Iowa, Illinois, Indiana 4 lanes. And that pre-egr Detroit with a bully dog ported/coated manifold and Borg Warner non waste gate turbo can really pull a hill. It is so nice to not have a valve trying to make my engine eat its own waste, a urine tank I have to fill that squirts in the exhaust, and a blast furnace under the truck to burn my stacks brown.
And for $40,000 less than a comparable spec'd new truck! No sales tax, no FET, no emissions junk. What a country!