I just bought a 2004 f150 lariat 5.4 with 49000 miles, when i bought it the average trip meter said 14.0mpg, but when i calculate my gas mileage it says about 10 to 11, and my average trip meter continues to drop almost below 12mpg now. I might have a little bit of a lead foot but is this normal for these trucks?

 

Winter blend gas.

 

Also depends on hwy vs city percentages. But 14-15 is about tops you will get, unless you always drive downhill with tailwind!

I also concur with the drop in mileage due to winter gas that has more alcohol in it.

 

Yeah, the 5.4s are not well known for thier fuel economy.
I have a 97 5.4, CAI, headers,run 93 octane, 4.10s and 285 A/T tires, and I get 10mpg. but thats all day long no matter the condition or load.
It's like I told my g/f started B#%^ing when she noticed how much I spent on gas a week. Its not a car,

 

A tech on a Lexington, KY radio show said that there is an average drop of 25% in the winter months.

 

Winter blends, colder air intake temps, more idling to warm up the truck, lowered tire pressure, spinning/playing in the snow, etc.

It adds up...

 

well i did check my tire pressure today and it was at 32psi and it specifys 40psi cold pressure, maybe that had an effect. I put it back at 40 and well see on the next tank.

 

get the edge evo programmer it'll boost your fuel mileage and depending on what size tires your using that will affect it also

 

You shouldn't need a programmer to get better mileage - the OEM setup is optimised for emissions and MPG. There is not a lot of improvement left to be had unless something is wrong with your engine.

My 2010 (bone stock XLT 4x4) gets well over 20 MPG on the highway in the winter (manually calculated). It's sweet to be able to go well over 700 miles per tank without having to stop and fill-up. Those who have installed aftermarket programmers don't get a significant MPG boost. In fact, most of the ones I know or have heard about get worse MPG with a programmer.

 

Going from a stock Edge on 87 Tow to stock, I went from 15.5 to 14.5. The stock programming is tailored for old people who want the most comfortable ride, even if it means sacrificing performance.

 

I've never gotten 20mpg on anything I have ever owned, I had a 2006 grand prix gxp 5.3 with displacement on demand and only got 14-15 mpg and those were supposed to get well over 20 highway. I do drive a 2006 E350 work van with the same 5.4 motor and get 13mpg all day with weight in it, so maybe there is something wrong with my engine, it would be my luck. It runs great though, so who knows

 

I think I see a trend here........

GET YOUR FOOT OUT OF THE FIREWALL.

 

It goes both ways! lol depending on how you drive it you can get better or worse. drive it like its stolen and youll see it drop but you ease a little and the programmer will increase mpg!

 

Im not driving it like a sports car, thats just a waste of time, I drove it like a grandma would and got the same results. Any idea of what I could check to see if its effecting my gas mileage, I get the same gas on my truck at work, which is a 2006 Isuzu 14ft box truck.