My truck does it but I thought it was wrong when I first got truck so I did it myself and got the same as truck

 

I've got an 08 lariat 4x4 screw, 5.4 liter, 3.73 gears. I run 5w30 synthetic oil and full synthetic in both diffs and I consistantly see 19mpg hiway and 15mpg city.

 

Post a pic of your gauge that says 26mpg... Thanks!! Before mileage and after...

My little V6 commuter...

 

Nothing you can do will make a truck get that kind of mileage in the real world. His math is off or he's full of ****.

 

Maybe his computer is set for larger tires? Previous owner had 35s and got the computer re-programmed and then went back to stock to sell and didn't bother with it

 

That's my guess

 

15.6 according to Torque. About 15 even when doing it by hand.

Edit: Supercab, 2wd, 4.6, Gotts mod, stock tire size. Two of my tires are rolling on lighter steelies, though.

 

2006 King Ranch Screw 4x4, 118k, 33x12.5 Toyo MTs, Rancho Quicklift struts, Bestop soft tonneau ... 11.8Mpg (with "summer" gas).

Recently had new plugs put in and throttle body cleaned, too.

This is based on the in-cab computer, which I recently reset (about 300m ago). Maybe the tires are throwing that off?

 

That's about what I'm getting with pretty much the same setup

 

2005 FX4 F150: 2.5" HBS Level, 18x9 XD Monsters -12 offset, 295/70/18 (34.6") Nitto Trail Grapplers, Flowmaster 40 series with Chrome tip.
Got new plugs and 1 new coil to fix my shudder 2 weeks ago.
Getting about 11.6 mpg with regular gas. 12 with premium. And I only get my gas from Shell. (Don't ask me why because I don't know)
Edit:this is mostly city driving. Haven't taken him on a road trip yet as it just doesn't make economical sense.