p38fln

Mine with 265/70R17 and 3.73 gears is humming at 1,950 RPM at 70 MPH - Not so good for fuel economy empty, but is right where it should be if it's got a load on it. Look like it's around 1,675 RPM at 65 MPH and 1,500 RPM at 55 MPH.

Seems to get the best fuel economy at 1,500 RPM

mrpositraction

95% city, lots of stop and go, 5% highway for my 5 mile stretch to work. I get on the highway, up to 75mph, hills inbetween, and then off 5 miles later.

SCrew, 5.5' box, 3.73 gears

14.5-15mpg consistantly

My 5.4L's (had multiple) on this same route would best 11.5 mpg. V

I am very happy with the mileage thus far, 1500 miles so far

spdmpo

3.55 gear 4x4 18" wheels. I get a very solid 19 mpg on highway driving 70. I get 17 in mixed driving. Admittedly this is driving very nicely. If I burn a tank and accelerate aggressively I get 14-15 mixed. YMMV. Its obvious the economy people state they get is greatly effected by driving habit and style. Im very pleased. So much better than my PSD and the fuel is cheaper to boot.

This is with 87 octane. I want to try 93 and see if that improves but im not expecting it to change.

dukefanatic00

3.73s 4x4 offroad 20" wheels. i run only premium fuel (93 here) and on my drive to work (one way 60miles) all highway and very hilly im getting 16.5-17.5mpg on 4 tanks so far and keeps getting better each tank (2200miles on my truck now). VERY CONSERVATIVE driving as well at 65-72mph the whole way

RHINO 13

You do not need to run premium fuel.

dukefanatic00

directed to me? either way , i'm pretty sure most know (including me) that you DO NOT have to run premium fuel ...... some like to do their own thing with their vehicles and just like the oil changing thread, people are gonna do what they want whether it be changing their oil at 500miles to feel better about their truck or running premium fuel bc they feel its better to do with forced induction or whatever the reason

dcfluid

New FX4 with only 140 miles on the odo, the eco with the LT tires just did a hilly 40 out and back highway run.
19 to 20 mpg avg on a cruise at 62 mph with a few passing bursts and 1 long double lane hill.
I was hoping to see 10% better as I do this run in all my vehicles a test.
I will redo after 1000 miles, and after 1st oil change.
My impression is the 3.73 gearing is too low for empty economy and if you don't need the max tow pkg or the FX4 then the 3.55 gears would be ideal.
62 mph turns 1700 rpms.
Speedometer is 2% optimistic.
City mileage has been more pleasing but no hard test yet.

spdmpo

I think we all know this. But have you read the manual? It suggests that in certain circumstances premium fuel will provide increased performance. I want to try it and see.

Spreg

Have a 4x4 Screw Lariat with 18" wheels and a cover on the back. It was one of the first ones off the line. Have had it for a almost 2 months now. About 2700 miles on it. Mostly mixed driving between city and freeway and have been consistent with 16-16.5. Can get 17-17.5 on the freeway at 70-75. Hoping to see a little better once the full break-in period is done.

tzolk

Are we under the impression that our ecoboosts have a 6th gear ratio of 0.61:1 and not the 0.69:1 found on the 6R-80 trans for other models? I am and I have seen it in a non ford publication however the real world rpms do not concur with multiple rpm calculators using the 0.61:1 ratio. Unless the speedos and tachyometer on the dash have a large error factor. We all know speedos have error at Hwy speed, maybe 1-3 mph. I've written to ford to get an official answer. Still waiting.