[LMMnewbie]

13.5 mpg empty with 80% on the hwy 20% in town... both cases using a light foot to see what I can get for mileage. There is about 2500 miles on the truck so far, and the mileage test was only done over the 200 miles since I bought it last week. I was fooling around tonight testing an Edge chip and running a few quarter miles and my mileage was 9mpg over the 17 miles I accumulated during the testing. All of this info is from the DIC and most of the time with a full 55 gallon tank. (the previous owner replaced the stock tank with the larger aftermarket tank) I am in Edmonton Canada right now and the temp has been around 32F (0C) during this testing. The diesel sold here is much thinner during the winter season and I was told by my bulk dealer that it has approximately 18% less btu per pound than the summer fuel sold here. I have driven several Dodge diesels for about 200,000 miles in the past and have not noticed a reduction in power during the winter fuel season. Also this truck is a crewcab dually with Toyo Open Country tires.
I am amazed at the wide variations in mileage within this thread and have to wonder if some of the good mileage #s we are seeing are from drivers in the far south whom are using our equivalent of summer fuel. I also wonder if my truck would be more efficient at 180* + since it is only running at 170 now. I will try a winterfront and much more accurate tests as I travel south into warmer climates and regions that sell thicker diesel.