What are some of you guys getting in gas mileage out of your 5.4?? I've got a 5.4 in my 2000 F-250 4x4 and its not looking good at all. I just got the truck. It only looks like im gettin about 10 or 11 miles to the gallon. What can I do to help it out??

 

when mine was stock... 13-15mpg
after all my mods (see my signature)... 15-18mpg
It all depends on how heavy my foot is, and get this, I get better mileage on the highway driving 85mph than I do on the highway driving 65mph ever since I installed the Flowmaster cat-back. When I installed the 2.5" leveling kit, I lost about 1.5-2mpg, with the truck higher off the ground and level it lost some of its aerodynamics it think. Also, the colder it is outside, the worst gas mileage you'll get. The colder the air, the more O2 is in it, which makes the computer dump in more gas to keep the correct air/fuel ratio.

 

Change the plugs, who knows when or if that was done, use Motorcraft plugs, put silicone dielectric grease in the coil on plug boot that sits on the spark plug. Change the PCV, clean with throttle body cleaner the throttle body obviuosly and the IAC located on the t-body elbow. Changing the coolant might be a good idea unless it's good. Your mileage is not too bad really. You can change to electric fans and a programmer added to an exhaust system and a cold air kit. These will all net a max of probably 4 mpg improvement with the mentioned maintenance. Heading into winter is not a good time for many to judge gas mileage either.

 

What gears do ya'll have?? I've got 3.73's. What mod would you do first in your opinion??

 

I've got 355 gears and I'm not doing much better gas mileage. I get about 13 maybe. One thing I calculate my mileage based on how many miles the odometer says I've went but the previous owner put oversize tires on it so that throws it off a bit. the truck originally had 225's it now has 235's. I figure that lowers my mileage by about 10% I need to get the speedo calibrated. I've done a complete tune up and while the truck runs better it don't seem to have made much of a difference in fuel economy. I think this is just the way it is..

 

I put 295 miles on my truck today and pulled 15.9 MPG. I can get about 17 MPG in the summer when I dont have to run this winter blended crap. This is with a 2004 F150 FX4 with 63000 miles and cruising at 68 MPH I am pretty sure it has 3.73 gears in it.

 

I average 13.5MPG. The biggest fuel economy increase was from adding my tonneau cover, it went up 1.2MPG.

 

Dont you watch mythbusters!! The tonneau cover has been proven a myth with serious testing. But on a more serious note, keep your foot out of the pedal.

 

I was getting around 13.5MPG when I bought the truck new. After installing a Borla SI/DO I'm down to around 12.5MPG.

 

Different conditions yield different results.

 

im thinking about a flush mount toneau cover for that reason.... They look good IMO.

 

Is your 250 a Super Duty?

JMC

 

i can get anywhere from 13-15.. depends on my foot..

 

I kinda remember that mythbusters, something about a half tonneau cover yielded better results then a full tonneau or canopy or tailgate down. Circulatory air moving over the cab into the bed somehow had less resistance and actually helped...I dunno. I had one though and they look nice

 

my dads 06 f350 super duty 5.4 crew cab short bed stock got 13- 17 with the superchip he got 13-19 with 7 people in the truck.