fuel milage
 

Ive got a 04 cummins 6 speed. k&n intake 5 inch exhaust, bullydog on tow. The truck also has 8 inch lift and 37 inch tires. I can only get 13 city daily driving. 13 interstate. Now yesterday we went up north pulling two snowmobiles and i only got 9.9. I know the lift and tires dont help but i had the same setup on my 01 dodge and would pull 17 and 14 towing. Is there anything i can do to make it better?

Get a smarty and tune it right!