I don't know how some guys get those high mpgs. I have a 2010 F150 5.4 3.73's and am hard pressed to get 18@65mph. Anything over 70mph and I'm in the 17mpg range.
You can thank your State Legislators for bringing you this:
New Oregon E10 Mandate Takes Effect
Oregonian (Portland, OR) (KRT): Jan. 15 -- Beginning today, state law requires all gasoline retailers in northwestern Oregon to pump fuel with 10 percent ethanol, or E10. By fall, all gas stations in Oregon must sell the blend.
That knocks 5 to 10% fuel economy right there depending on many things, including how much water was absorbed into the ethanol, whether they blended more than 10%, etc.
Terrain in Oregon is a major penalty, as with weather.
Well all that makes sense, except for the weather? whats wong with clouds and rain? Hey it's green here.
The OP being closer to sea level helps too. On a completely flat road, with CC set at 70, if I reset the average mpg computer I can see 20mpg. That is with my 6150lb curb weight 4x4 Expy EL with 3.73 gears and lousy E10 CA gas. Unfortunately where I live, the roads don't stay flat long and hills quickly drops that to 15mpg.
2007 Expedition EL 4x4 Tow pkg
1981 Palomino Pony, the PopUp = PUCampin! (Sold)
2006 Pioneer 180CK = (No more PUcampin!)
In my Ford F-150 owner's manual, Ford recommends that Tier One gasoline be used in the F150. You don't find tier one gasoline everywhere, but the manual does list the brands that do sell tier one. The interesting thing is that Tier One gasoline can contain ethanol and still be tier one. I am a believer in Tier One Gasoline. The few times that I have filled up at Sam's Club or Walmart, I have seen my mileage drop by 2mpg empty over what I get with Tier One Fuel. I haven't tested non tier one towing because I believe the engine needs the best fuel available if it is going to be worked hard.
Ford also recommends synthetic oil and transmission fluid if you are going to be towing extensively. Both reduce internal friction and both cost considerably more. I suppose only time will tell if using synthetics will pay off in the long run.
As it stands right now, I am very pleased with my F-150. I get very good fuel mileage empty and since I discovered that turning off the anti-sway on the computer increases my towing mileage, I am one happy camper!!
I hope this thread has helped some fellow F150 owners realize that they don't have to settle for 9 mpg while towing. If it did that, the thread is a success.
Off topic a bit, but a Nissan Versa that we bought specifies that gasoline with Ethanol be avoided because the computer expects pure gasoline and that if it were used, performance would suffer. Ford made no such claim in the F-150 Manual.