haha no its not that, its just that at 70mph im running close to 2600rpms and i can watch the fuel guage drop having it wound up like that, so i usually keep it at about 65 and the rpms are at 2400. with the 32inch tires i recently put on make it way better now though, and its a single wheel truck

 

 

I got between 14 and 15 if I didn't drive like a psycho on 33s with 160k on the injectors on stock tires. 6" lift + 35s still with 373s I dropped to around 10. put "marine" injectors in it, but regardless, reman'd injectors, I bumped back up to 14ish. This was when I was 15 and 16, but the absolute best I got was from west yellowstone to wells, nv. All downhill, and that was 20 or 21. On the way back I was back to 12-14.
The mileage wasn't great, but I was able to tank the mileage a lot lower on the dmax (just over 8) loaded down than I was in the 6.5.

also, if they blend the fuel where you are, its pointless to calculate your mileage during winter. Even my jetta bounces between 35 and 42 here depending on the fuel during winter. The winter blend fuel will REALLY screw with your numbers no matter how you drive.

 

no kidding i have been trying to drive slow to conseve fuel but with the winterblend it just sucks fuel

 

How would i find out if missouri has winter blend diesel? Is there a site to see what states have it?

 

Here they normally post it on the pump, but you could ask the attendant at a truck stop, they should know.

 

I cant get over 10 mpg in the 6.5 but I used to get 17 with ford international 7.3
more engine more power more mpg What I got to do to the 6.5 to get 15+? BTW the
7.3 would smoke the tires in the first 2 gears and still get 17. the 6.5 has the take off of
grandma's moped.

 

maybe you should sell it and get another ford then

 

the newer fords have too much electronics on them. that ford was pre electonics no computer. just did all the adjusting on the pump timing and the injectors.

 

have you checked to see if your vacccum pump is making the right vaccum amount. i bet your turbo wastegate isnt closing all the way