Recently completed the annual holiday/hunting pilgrimage to upstate NY. Basically put 2000 miles on the clock towing ~3000lb and carrying another 2000lbs with dogs, wife, supplies etc. FTR, I have a heavy right foot and have no issues running 80+ mph. Average fuel consumption was 14.2mi/gal. There was no real difference in mpg from the DIC and hand calculated figures (I typically can pump the same amount of fuel into the tank that the DIC says I consumed). Fuel mileage figures are slightly overstated as the speedo w/stock tires registers 1.5 - 2 mph faster than the GPS reading. I did not see any difference in running ULSD or LSD.