I've read for a long time that the Cummins got better mileage as it got more miles on it. So I bought my '95 in the year 2000, and I checked my mileage pretty frequently for the first two years I had the truck, and the best I got was 21.5 or so. I'd measure the MPG over 500 miles at that time, to try to get an accurate reading. So I had to take a 700 mile round trip last week and I measured it again and I got a tad over 25 MPG for the 700 miles. Most of it was Interstate driving, but I had an easy 800 pounds of tools and cast iron in the bed of the truck, and I also did about 100 miles of city driving. I'm feelin' good!

 

Dad's neighbor gets about that on his 97, IIRC he was around 257,000 last August and that is on ULSD.

Dad's 94 only gets about 12, but its a V-10!