I have the 5.9 with Edge on the mileage setting. Over the weekend I went from Austin to Port Aransas and back after staying for a nice weekend. The meter said 21.5mpg on the trip down. After driving up and down the beach and all over town it was down to 19mpg on the meter. By the time I filled it up back in Austin, the meter said 20.7mpg, hand calc'd was 20.5, so it wasn't off by much at all. I did have to drive 65mph to achieve that MPG though.

 

right now im avg 15.2, mostly non highway, even tho highway isnt much better, or so my overhead console tells me, but that'll all change when i get rid of that DPF!!!!!

 

I have a 2007 6.7L CTD Quad SWB 2WD Auto.

I've been getting the following averages.

around 12,700 miles on truck at end of year.
January - 2923 miles traveled (15.3k on truck) - 17.67 MPG
February - 2965 miles traveled - 17.98 MPG
March - 2469 miles traveled - 18.15 MPG
April - 3365 miles traveled - 18.69 MPG

now at 24,100 miles

Best MPG was 21.33, Worst MPG was 16.80.

Most of miles are highway (65-75 mph) with some city travel.

Only modification made was muffler elimination kit (Geno's Garage)

 

Over the past week I tracked my milage with the 5.9 and got 21.5[sm=bounceybounce.gif]. I was running on the freeway at about 62 with cruise control on with 2 stroke in the tank. Its the best I have seen so far so I was pretty happy.