I have owned several modified ford diesel trucks but this dodge cummins i have now is my work truck & stock besides the air cleaner.
What is the best combination to get the most MPG?
I drive 200 miles a day without a trailer.
2003 Dodge 2500, crew cab, long box, 5.9 with automatic, & 305,000 miles.
With this high of miles im afraid to add HP but would like better than 18 MPG.

 

mines a manual 4x4 with 35's and a lift and can easily get 18 with my steup. Best Ive gotten was 23.8 this summer going south on a road trip.

But open up the exhaust better intake and my truck is always on lvl 6 on my Smarty

 

O, Yes i forgot to saw the exaust was cut off between the cab & box.

 

im a solid 19-23. with the manual. how much weight are you hauling around? you might be able to gain something there.

 

How fast do you drive? How much town? How Meany stop lights? How much do you idle? There is a lot of how you drive! I get 19-20-21 it is jest how hard I push it. In town from 18 to 15 and that is how Meany stop and go. I live in a town that has 8 stop light I try to miss then all I can 18 in my home town.

 

Best I ever got was 25. Not typical and I was coasting and driving like a old man. Normal is 18-19.

 

check valve lash, keep rpm below 2100, don't use cruise control, avoid erratic acceleration. oh yeah-work it occasionally, or you'll ruin it. happy motoring!