I have had two now. An 04 and now a 07 quad cab 4x4s. I think in 06 they came with the hemi that dropped down in cylinders. Starts out using all 8 then to 6 and then to 4 if the highway conditons are good. I have found both to be pigs on gas but the 07 (with dropped down cyls) seems to have decent hwy mpg. Last spring the truck was only 1 week old and we took a trip to Carlisle, 902 miles one way and got there easily on 2 tanks of gas.