15.88 calculated, 15.9 on overhead. This is about 75% city & slower mountain (<45mph) driving w/ a dealer fill up. I built a spreadsheet. I'll post the results every 1/2 year or so. When I was first considering a diesel buy, I searched for MPG data so I hope this helps someone.

 

Wish MY milage was that high for local - course running 4:10's will get you no where in that catagory! LOL

 

That's the same as my 1989 dually gets on the highway in a rainstorm. (that's the only time I have checked it.) Since the thermostat was missing it was running cold at the time. It might get better mileage now.

 

Just filled up. 17.16 MPG with DC traffic, lots of city driving and no load.

Not to bad.

 

I've been real happy over the mileage my truck has gotten. After driving it awhile, the mileage dropped for no reason apparent to me. Then I read where max tire pressure would give better mileage so I jacked it up 70 psi (I had lowered it to 40 psi to get a softer ride). Lo and behold, I'm now getting a mileage that you would not believe (so I'm not gonna tell up and have you call me a liar)!

 

My first fill up was 18.2mpg manual calculation. Have not set the overhead yet.