Hey Jason P - Just curious..what years where your other cummins and what mileage did they get..from stock to modfified, standard, or auto, did they have 4.10 gears, etc? I am curious that's all. My 02 extended cab, 4WD, all stock, 265 tires gets average 15.8 mpg - that's pretty darn good..esp for stock! I do have a gentle right foot though.

 

I used to get 18-19mpg on 150hp injectors and hx35, now I can't even get 14, but my current setup makes it damn hard to drive like a civilized person, and it's not exactly a mileage saavy build either

 

you get 15 MPG????? I have a 98.5 with 265 70 17 I get 22 Highway and 17 city, and shes stock, Take the suggestions above but i didnt see anyone tell you to do you Valves, they make a Huge Difference, I was getting 15 MPG City when I first go the truck since the Valves its 17 and 22 highway...

 

Gotta luv Empty Wallets repsonse - that is hysterical and very understandable too!

Noted on the valves. They have not been done. Thank you.

 

99 24 valve slight mod around 22( automatic) 03 six speed best one slightmods 23 everyday 26 on a trip, 06 megacab automatic 22-23 slight mods and believe it or not got rid of 2010 for my current 02 no mods peformance wise 14mpg had a disagreement with the service dept on what mods could be made to the 20 and not void the warranty so as to not have to deal with them any more found my 02 from an older gentleman and sold the 2010