I managed 18 city 24 highway in my 5.4L F150 (2WD). Of course this was done accelerating really slowly and driving 55 mph. At 75 mph I got 17 mpg on the highway.

Cheers,

Pete

 

If we are talking about other vehicles,,,,,,,,,,,,,,,,

I can get 35 mpg in town in my VW TDI(diesel and no where near stock)
and that driving like the cops are after me..
Hwy at 110mph I get 42mpg,,,(not done much),,,,,,,,normal driving I get 38 to 40mpg intown
hwy mpg is 48 to 50.

Its fun to drive but when I get in it I feel in a hurry,,,when I drive my Rover its
OK to get there when I get there its nice to drive in a different way.

In my Land Rover I get 12.5 mpg in town and 16 to 17 hwy mpg O and its a little
stock still and its a Gas V8 non Turbo.