I just did a 1,200 mile drive with my 6.2L Crew Cab & 373 gears.
Tank 1 80 to 90 MPH, 12.1 MPGs, high speed highway traffic.
Tank 2 40 to 60 MPH some stopping due to traffic. 16.1 MPGs (best ever for me with this truck).
Tank 3 & 4, it was night pretty much straight 74 MPH, 15.1 & 15.0. A few slow downs and stopping for road construction.

 

I have a new.F350XL coming up on a thousand miles and I've been getting 15 mpg hand calc but the last tank I started locking out fifth and sixth in town. I thought the mpg would go up like maybe the truck would appreciate being in a more efficient power range but no it took me down to 13.5 mpg on last fill up (today).

But like many here I feel so happy to be out of a diesel with no warranty. I'm 2wd BTW

Possible highjack but do I need to avoid high EGT's in a gas motor like in a diesel ? Obviously lugging can't be good whether gas or diesel.

My XL is really stripped down I had to go to the junkyard to get floor mats!

 

You give me hope.....Thx!

 

Superduty with a 6.2 gas mileage is not good. Wrong vehicle with the wrong motor for mileage. I get 9-13 normally leaning towards the 9 but it does what a Prius won't.

 

My 2wd cc with 3.73's gets over 17 mpg (hand calculated) on the hywy (empty) @ 60 mph.

Gets 9.5 mpg pulling a 20 ft enclosed @ 7500 lbs

 

Last year I made a 240 mile roundtrip to pick up an engine and trans while pulling my 16 ft open car trailer.
Topped off the tank before leaving and then went back to the same pump upon returning and topped off the same way and had a hard time squeezing 14.6 gallons into it.

16.4 mpg

Oh yeah, my truck has 107K miles on it now

 

My truck gets it's best @ 60 mph.
For every 1 mph higher, I lose .1 mpg

 

It does seem the truck gets the best mileage in the 60 to 65 MPH range. I was pretty happy to break 15 running 74. I did notice that towing my open car hauler, empty, doesn't hit my highway mileage much.

 

Hi everybody and thank you for the shout out Rzr-runner1987. If you guys are wanting better fuel mileage we have seen average 10% gain with our tunes. It all depends on your right foot.

 

Probably a fluke but I just turned out a 16.74 mpg hand calc (150 miles back and forth to work and then a 220 mile round trip to the big city). I'm right at 2800 miles now.

 

Last 1000 miles I'm averaging 14.1 mpg. All highway I get 16mpg

 

10mpg here. Overall combined towing a three horse trailer about half the time.

 

I need to hook my truck to something REALLY HEAVY and run up and down some hills all day I think it would really help my motor wear in.

 

Here is a spreadsheet of a year of mileage data. I know it is not a 3.73 but this is my real world data. As you can see I have both the computer mileage and the mileage divided by the gallons. I don't do a lot of highway driving and I occasionally pull a 30' single tandem deck over trailer and a 16' utility trailer when I do pull. I have about 12000 miles on my truck as of this writing. The spreadsheet is an xlsx file saved as and xls (the forum won't accept an xlsx spreadsheet) so it may give you a warning when you try to open the file.

 

In the dash computer I did 8mpg hauling my horse trailer last night. And it only had two horses in it. Brutal. But I was giving her and I had to drive through a stop and go city for about 1/4 of the trip.