I've got a 5.4L, and I always get 12.1 MPG. I didn't buy the truck for gas mileage, so it doesnt really matter.

 

That's some interesting info. I always thought the main relation between PSI and MPG is that the when the tires were mushier, they created more rolling resistance. I never thought about PSI changing the whole ratio.

I wonder what happens if I pump 'em up to 40?

XXL

 

2003 XLT 5.4
I get 17 being careful. 13-14 lead footin' it.

 

Smaller tires will raise your rpm which will ultimately lower your gas mileage, plus you get a huge increase in rolling resistance. The reason your mileage would be higher is that your odometer (as you note with the taxi's) will show more miles driven than you are actually doing. It would more than offset the lower mpg caused by the increase in resistance. Reality is you'd only be fooling yourself, not the gas pump.
Howard.

 

I get 10.9 to 11.2 or 3 most of the time in standard city traffic. Highway mileage is much better 17 to 18, all on 87 octane fuel. I recently had the fuel injectors cleaned at Valvoline, and that seemed to help for a little while, more 11's than 10's, but now I'm back to the high 10's.

I run 34lbs front tires, 36lbs, rear tires, on a 2000 5.4 ltr 4x4 Eddie Bauer. Rear axle is 3.55, Limited Slip, running Goodyear Wrangler RTS P265 70R 17 tires. Although the original window sticker (which I still have), says to expect between 10 and 14 city mpg, and 13 and 19 mpg on the highway, I am jealous of anyone who even gets 12, 13 or so. I feel like I got better mileage when she was newer, and now has 41,000 miles.

I seem to remember an article in USA today about 4 or so years ago, about octane and its correlation with power and MPG on the Ford 5.4 liter. It said that the stock programming on the chip would automatically advance the timing according to the octane of the fuel, and that the MPG would rise with the higher octane as well. Anybody else aware of that?

I guess that I will experiment again with 93 octane for a few tanks (though its too much $$) and see how it impacts my MPG. My engine is all stock, and I would like suggestions for more mpg. Isn't there some sort of oil additive that will make for more mpg and less friction in cold weather? These freezing days have got to be murder on the piston walls! TIA

 

Sounds like I have some competition as the tallest Expy owner out there! I'm 6'11" and really appreciate the room too. I would like to know as well about the octane vs. mpg. I run my tires at 34 psi at all 4 corners.

Even my "all go or all slow" wife can't do worse than 12.3 mpg based on the computer. I run the 85 octane here in colorado except in the heat of summer and then 87. Never had a hint of detonation.

Any REAL computer chips or devices that can legitimately give a bit more power? I have been hesitant as I hear mixed reviews. I am a K&N disciple though.

My brother put a flowmaster exhaust on his 1994 4 Runner and upped his mpg by a legitimate 2 mpg, can an Expy benefit form this type of change?

Any ideas are appreciated.
Howard.

 

'03 Expy with 5.4.

15 mpg on highway at 75

10 mpg on highway at 65 pulling 5,000 lbs trailer

87 octane gas (the cheap stuff)

 

Howard, I am running a Flowmaster SIDO on my Expy as well as a K&N filter. I did notice a substantial fuel mileage increase after both installs. I would do it again in a heartbeat!

 

well i dont want anyone to get mad but i could get 25mpg on my 02 4.6 expo....wanna know how...ok fine i'll tell you when i get to the top of a hill i just shut it off put it in neutral and let it coast to the buttom of the hill....hee hee hee....

 

03 Expy 2wd 5.4 It ain't too great, but I get 15-16 no matter what I do. I have a Bullet bassboat that weighs about 2000lbs and I get 15-16 city, hwy, towing, it doesn't matter. But it is still better than the 01 Explorer 5.0 that I had. It got 14 city, 20 runnin 80mph to Melbourne, and 10 with the boat. And at least half of my mileage includes the boat.

 

5.4@70mph
320 mile trip
4 stops
about 40 stop lights
21mpg

 

BigMattXXL:It looks like maybe there is a divergance in mpg attainable with 4x4, vs without. Its a little difficult to tell, since not everyone has listed whether they get their numbers with or without the 4 x 4 package. I find it difficult to believe that a stock 5.4 liter can have this much variance otherwise. From 10.5 to 11 or so on the low side, to the mid teens on the high side in city traffic? The sticker on the 4 x 4 version shows 10-14 city. My research to date shows that with the factory programmed timing advancement based upon a fuel intake of 87 octane versus 93 octane could spell this difference, but the survey does not take any of this into consideration.

Thoughts?

 

2000 EB 5.4L 4x4 w/ 3.73LS - I get 11.5 to 12.5 with mainly city driving, push 14 on the highway.

 

Thank you 4by4freak, I appreciate your response. I have a front end noise that needs attention, and then I'll hope to get the Flowmaster on there if I have any money left over! My brother swears by it on his 4runner, and I know how lousy that was on mileage and power. Why run a 3.0 and get 15mpg when you can have it all and a nice 5.4 for the same mileage!
Howard.

 

True, the poll is flawed in that sense. I'll fix it next time around.



XXL