I just got back from a 5 day 2065 mile trip on witch I got 18 mpg according to my on board computer. It was mostly interstate and highway with some in town driving. I keep it at about 75 mph on most of the interstates. I don't think 18 mpg is to bad for a truck with a V8. I normaly get about 15 mpg driving around town. What do you all think?

Not too shabby.

I used to get about 19-20 hwy in my old truck.

way better mpg than 4wd

lot better than my explorer and i mean a LOT

i get 21 with my 96 silverado 3/4 4x4 w/350

I have an 07 Raider V6 and the best I have experienced is 19.6 highway.
It started out getting about 16 on the highway. Far cry from the sticker numbers.

The sticker numbers are 16/21 for the V6 and 15/20 for the V8. Your not far off. The sticker numbers are never right under real world conditions.

My 1997 4x4 V8 F-150 with 215k miles on it gets 18-20 on the interstate passin at 80-100 and cruisin at 80, and thats with 33" all terrain tires.
Around town is normally 12-14 depending on how much i used 4x4 and how much towing I did. Rarely will I see 15 around town, when the weather gets colder and im not runnin the AC ill get a little closer to 15 around town.