95 Shop truck does better on fuel than my 05 Ex........

[mjstef]

The 05 we just bought is doing about 11 mpg in town. The weather has been between 20 & 40* and i have not had the RPM over 2K What could be causing this low mileage?? My 95 F250 4x4 5spd 351W shop truck at work weighs 9K with all my tools and does a solid 13 mpg in town with 120K miles on it!! I would think this 3V 5.4 would at least do that. It has 46K miles on it. Might need a new PCV valve???

 

[lakmflx]

May want to change your spark plugs, fuel filter, air filter for starters and if that doesnt help get an injector flush.

I average about 14.4 -15.2 in town and on the highway it gets up to 17-19

 

[green03]

I think the sloppy converter on the 3v motors are causing poor economy at slow speeds. Try driving a little more spirited to see if it actually gets better. I am working on finding a good replacement converter that is tighter at part throttle but still stalls 2500 like the stock converter.

I have mentioned this before but trans shift/lockup changes could pay huge divendends here. The factory locks the converter very early because it is so loose which gets some efficiency back but then you are loosing your torque multiplication when it does lock up....
I am still waiting on some software updates to do tunes the 05 and newer Expeditions though....
I will keep you posted and let you know when something is available for your truck.....
Matt