I had a 2005 GMC crew cab 4wd with the complete Banks kit and cat removed. Truck had 285 tires. It would get 15.9 mixed daily driving . Highway mileage if you kept it under 70 would be 18.5 mpg. Towing a 24ft enclosed trailer at 70mph it would average 10.5 mpg. Drove it from new to 100k miles and wish I still had it. Have a new 6.2 Chevy and can not get over 14mpg empty. Jeff Wurl

I like hearing people's real numbers. Sounds like we are all close. I did get 19 mpg on a short highway trip over the weekend.

have a 08, cat/egr/dpf delete, tow tune with EFI live, and just changed all the diff/transfer case fluids to amsoil, trip down to charlotte 2 weeks ago got 19.5 calculated, now it never seemed to do that well before the fluid change but not positive. Thats with 285 tires and a flush camper shell, had always heard about people getting in the 20 range and never got close before, but never done much non-tow driving either..also tune was done to correct for tire size.

I enjoyed that post, so I checked mine around town 25 to 50 mph no towing old 2006 5.9 4x4 dually........and of course the pic rotation is wrong. lol!

2008 f250 6.4 all stock 85,000 miles crew cab short bed 4x4 nothing in truck nothing on hitch 10.5 mpg highway at 80 mph + truck says 14.5 mpg.

Was that on a lift or did you run it on jack stands?
That's great fuel mileage!

You must have been heading downhill to the West. That's the only way that number is legit.
And your tires came off a Schwinn or a Huffy.

I developed a carburetor for diesel trucks that got 100+mpg but the big oil companies squashed it and I can't afford to fight them. Oh well.

With a sail. Fiddy Cent took the pic, he holds the Samsung sideways like he's firing a Glock

06 LBZ bone stock. I see 15.5+ hwy and 10.5 towing 15,000 lbs on the digital dream meter. I changed the wheels up to the 17" that the new trucks are running but used tires that are near the OE size diameter for the truck so the digital meter could possibly be on par. I plan to do deletes and programmer so I will see how much change I get.

Love this truck.