To begin, I have a 2005 5.4 Triton XLT supercab.. I have the truxedo cover, running boards and bug deflector. I have done searches and dunno what my best route is to resolve my problem.. I am getting anywhere from 11.5 - 12.5 mpg My driving is about 70% highway and 30% street.. I have been doing my studies on my truck for the last 3 fill ups to come up with these figures. I know its still a NEW truck but I am at 2000 miles now and still getting the same gas milage as when it was NEW. During these tanks, I have not went pass 3000 rpms either. My fuel light comes on about 250 miles or less. I know this wasnt the best thing to do but I even let my tank run dry and I had 312 miles on 27 gallons of gas I did have 5 gallon can of gas in my bed for backup.. Im thinking of getting the PCM reflashed? If thats the route to go how I do I get my dealership to do it? I love my truck but little frustated because I would think I should have at least 15mpg. Thanks,
Chris

 

What size gears do you have? I have 3.73 and I can consistently get 16-18 or so. One thing you can do is bring your shifts down to about 2000, that helps alot. Another is drive at 65 that helps a bunch also. I know you may not like driving that slow but thats what it takes to get good gas mileage in a 6000 lb truck.

 

I consistently get 15-18 on my 04 5.4 is a little less now as we are getting winter gas not quite as good, your bug guard doesn't help anything messes up aero dynamics a bit but you should do better than that unless you are really roddin it but don't get to excited until yo have at least 10K KP I also have 3.73 gears.

 

I have an 05 screw with 2400 miles on it and I get 15.5 mpg. I have 5.4 w/ 3.73s and drive mostly highway. I drive at mostly 70-80 mph. A programer might help you but not from the dealer unless you need the tsb up grade.

 

I get around 13.5-15.5 on my 05 Scab XLT with the 5.4L. I have the 3.55 gears...seems OK to me for a big truck like this...

 

YOU NEED TO DRIVE IT HARD SOME TO BREAK IN THE MOTOR AND RUN FULL SYNTHETIC OIL. MY PA IN LAW GETS 16 + AND HE HAS A HEAVY FOOT ALMOST ALL THE TIME. GIVE A LITTLE HACK FOR A CHANCE AND SEE WHAT HAPPENS. HE GOT 12-14 UNTIL ABOUT 15000 MILES AND FROM THEN ON IT GOR BETTER.

 

BTW I have 3.55 limited slip.. Wouldnt I get better miles with my 3.55 then 3.73 gears? I will also change the RPMS up a little more when I drive. How many miles are on your trucks when the low fuel light comes on? I guess I wont panic yet and I will let the truck break in some more.

Thanks,
Chris

 

I've got an '06 F150 SuperCab with 3:55 gears...I get from 18.5-20 mpg on the highway and about 16.5mpg city driving...much better than the 12.5-14mpg my 2500 Silverado gets....knock on wood.....

 

Chris. I am having the same roblems that you are. 05 screw 5.4 , k&n intake, flow master cat back, and superchips computer programer. 12.5-13.5 mpg in city and highway about 1/2 and 1/2. It baffles me to? I cant seem to do any better. 10,500 miles.

 

Just an update, Im up to 13 MPG.. hopefully once spring rolls around I will be higher.

 

Although I do not have any experience with that particular engine, I would NOT advise you to have the computer reflashed just yet. From my experience, the service department usally messes up more things than they fix. Also all engines have a "break in" period when they are new. I would make the dealer check out the truck (they won't find anything unless a idiot light is on usally) but do not let them touch that computer. I seriously doubt that is the problem. More likely to be an aircleaner, O2 sensor, or even a bad sparkplug gap from the factory.