I've got 2003 screw with 5.4 stock for now I drive 15 miles city and 20 miles highway to and from work and average 16 mpg but I tend to drive aggressively so it could be better not much though.

 

I have a 2002 4.6 , 5 sp man, 4x4, single cab, short bed, I have a K&N "Cold" air Intake and hypertech on regular fuel installed. I have a tonnu cover and running stock (235/70r16) tires on California gas I am avg 14 to 15 in mixed hilly, city, highway driving. I have gotten up to 20 on trips up 101 at 55 to 60 mph but that is rare now. Whe I was running my 33x13 nitto's on 18" rims, I was getting 12 in town and 16 to 17 highway.


my 2 cents

 

02 fx4 scab 5.4 on 35s. No tuner. Only engine mod is Gotts mod. 3.55 gears. 15mpg if I baby it using alot of cruise control with mixed city/highway