04 4x4 Screw 5.4 3.37 gearing. I just took a trip to Danville VA. Averaged 18.9 up and back. Getting 16.5-17.5 in town. I baby this truck. Take off is usually never over 2000 RPM's. 70 MPH is 1950 RPM's. I do hotrod it sometimes and the mileage reflects it. I drive 70 miles/ day. It is a mixed drive some highway 65-70, some little towns.. 35-40MPH. The worst mileage I have ever seen in this truck was 14MPG. Mods done are an Edge EVO and Flowmaster SIDO 50 series. I also have a tonneau cover. This mileage blows away my Expedition that I just traded in. Best seen on it was 17 on a 900+mile trip. The mods didn't improve MPG much but it is much nicer to drive now. The low end torque is awesome! I am setting it up to tow a 8000 lb Travel trailer right now.

 

Geddy them 258 miles is awful. i have a fx4 w/ 3.73 and i get gas when my light comes on. i get 15gals and go 225-230 miles every time. on 24 gals i've never gone under 400 miles. 425 being the most i've gone on 24 gals. there has to be something wrong. is this a new truck or did you buy it used? how does the truck drive? where does it idle at? these are some of the things that will be needed to be know.

carbon built up in the throttlebody could rob gas. but for a 2006? i would'nt think so. a problem in the pcm is very likely, but you should see some result from it, like a high idle, or high rpms in od. do you drive with od turned off? there is no reason a truck this day and age stock should get that pour of milage.

 

It looks like your in the same boat as me and yet we ar'nt getting what the other are or even close too it. I love driveing my new truck but I'am not loveing bying so much gas. May be the ones getting so much better then us are doing some of there driveing with the motor off???!!!111

 

I got 15 mpg average last tank with city and hwy miles. The truck has 2200 miles on it so far. The worst I got was 13 and that was mostly due to my wife and her short trips to the store and stuff. 5.4 2wd supercrew with over 1000# of tools and stuff on truck.

 

mines been hurting my feelings with 12, and its all city. Im headed to Rochester, NY next week, so we'll see what a highway trip will do. Its only got 2300 miles on it, and there's a reason. I'd rather put premium in my Cobra and get considerably better mileage.

 

Wow, you guys should have bought a V6 like me, the only time I see the gas gauge move is in town and then it gets about 16 city. When I'm on the freeway going 70-80 mph I don't see the gauge move even a needle point. On average the needle will move a little (width of the needle point) every 20-25 miles. The reason I bought the new truck was because I thought my 1979 F250 4X4 with a 460BB got horrible gas millage with an average of 9mpg, and it has 33x12.50 tires with 4.10 gears and a no OD C-6. The freeway kills its gas millage since it does about 70mph top speed. It seems its gas millage is somewhat comparable to a new F150 5.4 4X4 screw.

 

I've been told formulated gas, especially in the NY and Boston metro areas, is notoriously terrible when trying to attain decent fuel mileage. I have an '05 HD SCab with 4.10 gears and average around 12-13 mpg. It makes no difference if I baby the throttle and never go over 2000 rpm's.
Short bed trucks with 3.73 gears running "unformulated" gas will do better as others have stated.

 

06, 4X4, Scab, short bed, 5.4 Lariat. with no mods.
I can't get mine to go under 10.8 mpg city driving. It is usually at around 12.7. Longest trip so far was an 80 mile jaunt round trip on the freeway. Using the fill up and divide method of calculating it got 17.3 mpg. The truck has only 803 miles on it, as I just pulled into the driveway a few minutes ago. So far I am happy with my mpg. I would like better, but these trucks ain't light. It takes a bit of go juice to get them moving.

 

I have an 06 Screw 4X4 Lariat 5.4 and I avg about 12.8 mpg. Drove from south Texas to Missouri and only got 14.2 tops. Sickening.

 

I talked to my dealer this afternoon and he told me that after it is broke in it will get better milage but not to much. He says that it will not get much more then 12 ever!!!! When I told him that I new guys who get 18 with theres meaning you guys hear he just laughed and says not to believe it that these trucks are made to work not to get good milage.

 

I have a 2004 5.4 screw with 40,000 miles. I recently got 500 miles to the 30 gallon tank. I can average close to 18 mpg mixed driving for a few days then I have to have some fun. I keep rpms below 2,000. In the manual it states a 15% difference in fuel economy (Don't quote me on this) between 55mph and 65 mph. Try some highway miles at 55 and NO A/C. I can immediately see a difference in mileage. On a more confusing note....Anyone heard of WOT (wide open throttle) driving. I was reading an article that said you should floor the gas pedal when starting out and let off when you reach the desired speed. Supposedly engines are most efficient when driving like this. I'm too scared to try. Theres no way anything so fun could be good!

 

Never heard of WOT(wide open throttle) driving helping out. It probably won't work well if your city driving all the time. I drive 18 miles round trip to work. Theres a few stop signs and 3 stop lights. As of now i have 200 miles and i am exactly on 1/2 tank of gas. I usually see 13.5 to 15.5 in city....around 18 highway... the 13.5 comes from WOT so I don't think it helps me. Maybe I will change my driving habits but then its no fun.... BTW i have an 05 SCrew FX4 5.4

 

I just got home from my dealer and told them I was not happy with my milage and they had me see the service tecknisian and also my salesman and the manager. They all told me that my milage is normal and when I told that some get 17 or more they all say they never heard of any body getting close to that good with a truck like mine and do'nt believe it if some one says they do. They said to expect to get 11 to 13 and no that it is what they all get. I'am going to drive it to work today and watch the gage all the way!!!!1

 

i have a big problem with this. for starters just say your truck aint going to get more than 12mpg. well your only getting 10mpg. dont sound like much untell you get out a calculater. so why aint he fixing your truck? that 16% less mpg than you should be getting by his statement. on average{this comes from what has been reported here} the 4.6L gets 18 and 5.4L gets 15mpg. i dont know why he laughed at you, theres to many people getting this kind of milage. go to another dealer..........

 

I think there is something to this. I watch my Instant MPG on my Edge and here's what I have seen. If i spend 15 seconds getting up to speed then my MPG suffers moderately (5-6MPG) for 15 seconds before it levels out and I'm back to normal MPG. If I speed up quickly (i almost never floor it) then I get horrible MPG for 4 seconds (2.5-4MPG) but then I spend the other 11 seconds getting normal MPG.

My '04 got a few more MPG than my '06 even before i added bigger rims, tires, and exhaust to the '06. They're both nearly identical. '04 FX4, screw, 3.73. '06 Lariat 4x4, screw, 3.73. I'm still breakin in my '06 though.