I have gotten 14-15 city from the day I bought my truck with 8 miles on it. Even with all the mods I have, I still get the same when I drive decently nice. If I am on it fairly often I'll get 11-13 city. Towing I get about 9 or 10. Flat highway driving (Phoenix to LA) I got 16.5, that is about the best I have ever seen it. I dunno how some of you get much over that, especially with 4WD, unless you drive like grandmas!

Or maybe there are some factory freaks out there that get really good mileage?

 

I have to agree with those who said to do a tuneup, I would definantly go through and replace the basic components, ie; plugs, wires, fuel filter, pcv, air filter, check the fluid in your rear end and transfer case just to be on the safe side. If you want to go the extra mile, a K&N filter isnt a bad idea either, But I would'nt spent $265 for a hypertech, or any program for that matter before i did a tune up. Good Luck

 

I used to average around 16 mpg with my old lift on my 1999 ecsb 2wd with 33's. half highway and half city. I get almost 18 average now.

 

I did retune for the 33's.