I am getting aprox 400km (250 miles) per tank. This can't be right? 4.10 gears. Checked air filter and it is pretty muched plugged but I don't think that will make much difference. Or is this the right milage.

Any suggestions?

2008 f259 5.4 4x4 crew 35" tires 4.10 gears

 

Try a new air filter.

 

what kind of driving do you do (highway or city?)

how big is your tank (do you have the long bed or short bed?)

 

Plugged air filter has the potential to knock out a couple mpg. Good luck with the 5.4 on 35's.... My wife's stock 07 Expedition gets 13mpg, about half highway, half city.

 

I get around 13 on my '08 4X4 CC short bed w/3.73. 25 gallons is about what I can get in it when less than 10 miles to E. If you have the same configuration as I do you are probably getting about 10 MPG, which I think would be about right with lower gears and bigger tires. Give better info about your truck and accurate mileage and maybe someone can help a little more.

 

My 2008 F250 power stroke gets 11.1 mpg at best im having the same issues with the mpg

 

25 gal tank? If yes then I'd not complain too much if your in the cold and snow.

 

The more I read posts regarding poor gas mileage on the 5.4L, the more fortunate I am with my new-to-me 2008. 3.73 rear, automatic, and 275-70-18 (32-in) tires and I'm pulling down over 16 mpg on the highway consistently and 12.0 around town. New Autolites, K&N CAI, Superchips Mileage tune, and a bed cover; the combination has resulted in over 1.0 mpg increase.

As others have recommended, keep the rpm below 2k.

Best of luck,

 

sounds like normal gas mileage to me for that engine. but you should set yourself up with a tuner first, then add those other mods (cai, exhaust, etc) as needed...but the tuner will help out alot...go to 5startuning.com and call mike...he's the man.

 

2008 f250 superduty. Engine has 35,000 miles, truck has 95,000. It does have 35 inch toyo mt that are so bald they may as well be slicks. Just purchased. Guy told me he averaged 14-16 mpg. I get 8.9 hwy miles and 7.9 around town. Last weekend we went camping and towing a small trailer got 5.5 mpg! I need some suggestions! Have livewire ts tuner, tried on eco87 tune. Also tried the tow tune and the factory 5.4 superduty tune and those have not helped at all.

 

I have always advocated that clogged fuel injectors are the main culprit of poor fuel mileage in pressurized delivery systems. Clean filters are important also, but injector spray nozzles that dribble fuel can rob your system of valued performance. I use fuel additives to keep my injectors clean and am a big fan of LucasOil products. If you don't use pure synthetic oil, you may want to consider switching. Synthetic oil keeps your cylinder walls from pitting and scratching and does a good job filling in those gaps. Your motor will thank you for it, believe me.

 

If your truck fuel mileage has dropped, check your brakes. You are probably have one or more sticking calipers.

 

So the thread was inexplicably necro'd from '11.....but this is the most sensible suggestion I've seen yet

 

Just trying to help the necro-poster.