1999 17 MPG/2001 14.1 MPG
 

I had a 1999 EB 4X4 back in 2000 it got 17/18 MPG up on the HWY which was Good in my eyes when we traded it it it had 1400000 miles on it.

Now I have a 2001 EB 4X2 for about 2 months now me and my wife like the the MPG not all that great it all stock and it get 13.5 MPG compaired to our 1999 we use to have any idea why it has 102000 miles on it.

I maxed out the tire pressure 40 PSI to gain some MPG but that did not help much.

I dont drive it hard at all no rabbit starts it a cruiser ONLY.
Same 5.4 engine the 1999 was 4X4 so I know it weight more so why is the 2001 eats more gas.

Oh ya the 1999 never blew a plug but my 2002 F250 did LOL but the F250 got 10 MPG on a good day going down hill with the wind behind you the 38-14-18 Inch tires killed the MPG even it was regeared for it..

good question, i also wounderd why my 98 expo would get better then my 2001 expo even tho the 98 was 5.4t with 4x4 and the 2001 had 4.6 4x2, but i after 2000 the mileage is less sensitive to change then the pre 99 under, i dont know why but i guess it does make a bit of since after the removed the instint mpg in the tripmeter after 99 or was 98?

Were the spark plugs changed at the 100K mile mark?

i don't know.

Well if they're still the original plugs, than that could be the MPG problem.