While I was in the forum I thought I'd mention that I got a ScanGuageII a couple of months ago, and with careful driving I now get better than 15mpg around town and better then 20mpg on long highway trips (a range of around 700 miles).

The original sticker states 13/17, I believe. I don't know how true to life those sticker numbers are but my impression was always that they were a little higher than you could expect.

 

Are you actually calculating your mileage by hand or are you using the "computer"? We took an E350 with a 5.4 to kansas a few years ago and got about 16mpg on average.

 

Both, really. The ScanGuage is calibrated against both the mileage and the fuel consumption between tank fillups, and is always about as accurate as you could hope for when sloshing 35-ish gallons of fuel in the tank.

 

I had a '98 Acura 2.5TL (2.5 liter 5 cylinder) which had EPA's of 20/25. I never got a tank lower than about 21 mpg (in the dead of winter, sitting in snowy traffic jams), and routinely got about 24 in mixed driving. On the road, it regularly got 27-28 mpg, and I once cracked 30 mpg. Of course, Honda was not pushing the limits of EPA ratings to make their corporate averages better. At the same time, my wife had a '98 Duratec Sable with EPA ratings of 19/28 I think, and it never got more than about 25-26 on the road.

I've got a 2002 E150 with a 4.6 that was rated at 15/20 (although this was for the empty box--it had weight added as a conversion, but no high top or anything like that). My lifetime average, for 66k miles, is about 16.5 mpg--and has been going down the last year or so because of the ethanol in the fuel. On trips, I've always been able to count on 17-18 and do NOT drive really slow (usually 70-80 mph).

I'm guessing that if I drove 60-65, I would see 20 mpg on trips with it. Sounds like your 5.4 is doing a squeek better than this, but I wonder if you're REALLY driving gently....how fast are you going on the road to crack 20 mpg?

George

 

I guess I rarely exceed 65, and I'm usually around 60. I think it's really more a matter of careful and smooth acceleration, coasting down hills, and anticipating the usual slow downs you get on freeways to avoid bunching up with others. Cruise control is OK but it tries too hard on climbing hills and that's a mileage killer.

 

My last E250, a '05 4.6L w/4.10 gears would click off 18 mpgs any day if kept under 70 mph. My new '08 E250 5.4L w/3.73 gears won't get better than 15.1/2 mpg. It also doesn't seem to pull a load any better ........ should have stayed with the 4.6L/4.10's!

 

Yeah, it's all about the rpm's I suppose. I get my best mileage at around 42mph, and the engine has just shifted up to 4th gear and is running at around 1150rpm (if memory serves).

 

Don't ever compare a 4.6 to a 5.4, they are totally different, the 5.4 gets far less MPG. BTW, my EXT 99 5.4 3.50 gears E-350 15 pass with all the seats but one bench is stripped out, I get 8-10 MPG city, it's killing me, I've been running E-85, on regular, I get 10 MPG no more.
A friend said his 4.9 95 E-150 got 16 city, I sure would like to have that.

 

I don't want to sound like a fanboy or nothing, but those plugin fuel gauge things are a real eye opener. You might want to beg, steal or borrow one (really you only need to drive around with one for a week and you've learned all you need to).