Our 05 Dmax work truck is a long bed extended cab 4x4 with the Ally.....it will easily get 20 mpg unloaded on the highway cruising at 68 mph.

 

I voted 20 mpg. But now with 35" tires it looks to be more like 19. I have seen 22.3 for a very best tank. And I only paid $1.17 per gallon for fuel then.
The trip to Indy this weekend I got 18.8 mpg with cruise set at 80 mph most of the time. Last year with 33" tires I averaged 20.6 mpg. (I didn't write down my speed, but I am sure it was close to the same.)

 

strictly highway to cowtown and back netted me 22.46 mpg at a steady state 68 mph (2000rpm)

Hand calculated in US gallons of course.

Not too chebby... it's a GMC!


Mind you this is the best I have ever had in mpg.

Same trip a week later was 20.4

Highway and commute 50/50 i see an average of 15.5mpg.

intown... well it is too hard to resist the loud pedal!

 

Mine gets about 17.5 in detuned mode. Mine at the lowest setting dynos 440 hp. In the high power mode it is about 2 gallons a minute.