A good method to quickly approximate your mpg (if you have the on-board computer) is to set your cruise at a certain speed (start at 55) while driving on a flat grade. With the mpg displayed, press "Reset". The initial value it shows will be the instantaneous mpg. If you continue driving non-stop like this and conditions (wind, grade, speed) do not change, you will likely end up with that mileage (+/- 1mpg, I usually get 1 mpg less than the readout when I calculate myself). You can now set your cruise to a higher speed and repeat the steps above to compare. You will see that speed has a pretty heavy relationship to mpg. By the way...I have a 5.4L with 3.55 gears, no mods.

 

The only correct way to compute milage is to do it mathmaticaly.

1. Fuel up to full
2. drive
3. enter miles driven
4. Fuel up to full
5. divide fuel into miles driven.

Hence, miles per gallon. This is third grade math!

 

I have maintained a spreadsheet of every fillup since the truck was new, 63,000 miles. Even make notes as to where I filled up, what was different about how I drove on that tank, etc. That was how I discovered there is a difference in gas. I always fill it up, too, no partials.

 

I drove to Orlando from Athens GA 60mph took me almost nine hours and i got about 23.3 mpg

 

I squeezed 21 MPH out of my truck in a 400 mile trip to my daugher's house. I held the speed to 60 MPH, no AC, slight tailwind, no load and the altitude went from 2500 ft at my house to 15 ft at hers. Normal driving in normal conditions on the same trip yields about 19. 13-14 in normal local driving.

 

I posted an MPG thread a while back where I tracked my mileage to test the validity of gains with an intake, exhaust and some other mods. I reset the trip computer at every fill up and also calculated my mileage. The trip computer was ALWAYS spot on...every time. I think those who claim it's wrong either don't know how to use it or can't do simple 3rd grade math.

 

2006 SuperCrew FX4
5.4 engine
3.73 gears

cruise control @60 mph for 2500+ miles. I got 19-21 mpg @ about 1650 rpm with 3 people and ~500 lbs in the bed

cruise @ 65-70 and I get about 18 mpg

want to guess which speed I drive

edit: the 21 mpg was without A/C or defroster on (winter drive). I get about 19 mpg with a/c on at 60 mph

 

Seasprite, I have the exact truck that you have, and on my last long distance drive, fully loaded for a hunting trip, and 75-80 on the road, i got 18. This was calculated by topping off to the last drop, going and coming, and dividing gallons into miles to destination according to my Garmin and odo. This mileage also included about 5-6m of 4X4 trail crawling. Now I have those "Nevada pinstripes" to deal with.

 

Well it looks like some mods helped out some people and others didn't have to I'm trying to figure a way to increase my mpg toward the 21 side without forking out to much money & negating the return. My tires are stock and at 35psi cold which is what I believe my door panel says to run them at. I only have 22k on the & all maintenance is up to date.

I'm not complaining to much because my 91 explorer 4x4 got 18 mpg with a 4.0 v6 versus a 5.4 v8 if I'm missing something let me know would you thanks.

 

I recently acquired a 2006 F150 XL std. cab 8' bed with 4.6l and auto trans. This pretty much new truck gets 19 on the highway running 70, and 13.5 in town. I would like to pickup a little more mpg in town. What has anybody else done as far as intake mods, cat back performance exhaust, Hypertech, or? More importantly, how as it worked.

I have seen things that suggest I could see 2-4 mpg better with some or all of these mods. Obviously spending thousands of $$ to chase a couple of mpg is rediculous, but spending $400-600.00 might make sense in the long haul.

I don't expect car mileage, but 13.5 going back & forth to work is killing me.

Thanks

Mike

 

I can get 20 out of mine if I keep it at 60...at 70 it dips down to 18...at 90 its about 15...in the city its about 14...my tricks are don't let the motor rev above 2K...slowly feed gas when passing cars (it typically won't downshift this way)...find a car to ride behind (but not tailgate) as to break some (and I emphasize some) of the wind resistance...

best figures:
24.1 MPG Highway: Driving from Dallas to Houston (at about 80, it is mostly downhill)
18.6 MPG City/Highway: Driving to Houston from College Station to do Xmas shopping
14.3 MPG City: Weekly commutes to and from the office and school
13 MPG: With 5000LBs behind me, at 65mph (I was on the highway, yes this breaks TX State Laws)

Worst Figures:
15 MPG Highway: Hottest point in the summer, A/C on Full Load
10.1 MPG City: Summer, A/C On Full Load.

All above figures were hand calculated.
Specs: 2005 F150 Supercrew/4.6L V8/4R70/2WD/3.73LS Rear/265-70-R17 Michelins

 

Yep. Stop and go kills mileage on these trucks. During the summer, I can get 20-21 mpg if I'm driving a lot of highway miles, and I keep it at 55 (even on the freeway). If I exceed 55, the mileage drops a couple mpgs. If I get get caught in stop and go traffic, or if I'm making short trips while the engine is cold, it drops to 16-17mpg pretty quick. Cold weather seems to hurt mpgs too, especially if I'm making short trips.

But if the truck is warmed up, and I'm driving on the freeway, it will get 20-21 mpg. At 55mph.

Dale

 

35 psi is about right if you have the P rated tires.

if you have the LT tires, you should air them up to 42-45 psi. the truck will ride better (less spongy feel), the tires will wear more evenly and you'll get better MPG

 

oh boy here we go!


Ray

 

I'm going to trow another part into this equation. It the terrain you drive in also. I live in Central New York where flat areas are not too common. I have a 2004 F-150 FX4 with a 5.4L. I have installed a Magnaflow exhaust, Volant CAI and use an Edge that is set for transmission only. I average around 15 MPG on city/highway driving. On a good long trip I can average as high as 18 MPG. Just wanted to add another factor into this all.