I'm up to 15.6 mpg on my 5.4. My first trip on the same road was 13.8 mpg. This was a 400 mile round trip run at 70 mph. The difference on the second trip was I have installed a Retrax roll top cover. I'll compare on the next trip and see if it holds. This seems to be the norm on the highway, anyone getting any better? Check out my pic's.

 

I dont think the on board computer is right, it says i'm getting 15.6 but its closer to 12

 

I took a 2000 mile with my brand new 2004 scab 5.4 fx4 with the 3.55 rear end. I put a tonneau soft roll up cover on it and stainless nurf bars. First tank of ethanol blend gas we got 17.4 miles per gallon. 70 mph for 300 miles. I thought good golly miss Molly, that is wonderful. The next tank of gas was 87 regular and drove on it until just about on fumes. 18.5 mpg at 70 mph. FANTASTIC... On the return leg of the trip, I wasnt driving for economy if you know what I mean, 75-80mph for 725 miles and averaged 18.2 mpg. Considering I used to own a Dodge ram that got 12 in town and 12 on the interstate My Ford is making me smile a little more when I pull into the gas station. Ezee1

 

Wow that's good mileage!

 

I'm getting similar numbers (18 +mpg, 5.4 engine FX4, regular unleaded Chevron), if I stay on a flat highway at 65mph. I use old fashioned math, and a Garmin GPS to judge the speed and miles traveled (by the way, at 65 actual mph, the truck speedo reads 68. When the truck reads 65, the GPS reads 62.5).
Larry

 

I sure as heck hope I get the kind of mileage when my baby comes in...

 

I sure wish everone got window sticker or better gas milage. Having the right octane gas for the computer settings is a start. 87 octane works the best for me. With ethanol 10% blend , I lose about 10% mpg or about 48-50 miles per tank. Back in the 70s some of us young collage students used to blend our own gas to increase the horsepower and the mpg. formula: 9 gals of regular gas and 1 gal of diesel. ( needed to readjust the timing and change spark plugs to the next number hotter) 1970 plymouth 18 mpg would do 25 mpg or better with the "gas-el" mixture.

However, I don't recomend this at all (college stuff)

 

But that Gas was differented then..............Right?

 

it was leaded gas at .42 cents a gallon. I dont know if it was all that diffrent from todays gas except for the lead . ( I now compensate for the loss of lead in my gas by having a little lead in my foot...LOVE MY 2004 FX4)

 

Better then Lead in your ***!

 

I'm getting about 15.7 mpg with mine Reg cab fx4 w/3.73 rear. Thats about 50/50 Highway and city Thats with an airaid intake and dual exhaust

 

I have a 2004 (build date 2/04) with the 5.4. It has same air filter tray you described. All the 04's I looked at had the same filter design.I wonder why some databases have the 04's needing a conical filter?

 

Dont forget thr 04 Hertiage, I beleive it has the "old style" air filter.