"Larry L" wrote in message
...
I'm very disappointed in my mileage, thus far ( it's still under 200
miles
and driven only short distances 'in town' ..yeah, yeah, I know they take
time to break in ) and if it doesn't get a LOT better, I'll be an unhappy
camper ( it has a read-out of mileage, so I fret a lot more than I would
if I was just doing the math after a visit to the station )

I'm not super familiar with the 6.7, however I noticed about a 1.5 mpg
increase when I hit around the 50 - 55K range in mileage. At this time, I'm
completely stock except an aftermarket Aero muffler and I'm running in the
21 - 21.5 mpg range empty at speeds between 65 - 70 mph.

I know what you mean about having the mpg readout. For the longest time, I
couldn't keep my eyes off it... I have found it to be fairly accurate. Early
on, it was about 1 mpg low, however has been pretty much right on when I
have checked the last several fill ups.

JT