brulaz

Wow, stayed in 4th at 65mph? That's pretty extreme. No wonder your mileage sucked.

Can't say that's ever happened to me, but I have a 3.73 differential and probably would have slowed down to get it into 5th. Maybe your differential is lower ...

I know the prairie winds can be wicked, my worst mileage has always been with headwinds. How big is the sail you're towing? Mine is pretty big: 8'x8'=64sqft.

Also Ford says to use premium gas when towing heavy.

acadianbob

I've towed a 5,500 pound RV trailer over 6,000 miles with my Eco FX4 with 3.73's. My overall towing average is 11 mpg at 60 mph. It spends virtually all of its time in 6th gear. I've seen 4th gear maybe 3 times on some severe hills. The worst I ever got was 8.5 mpg into a 30 mph headwind.

The most common reason for my truck to use 5th instead of 6th, is a low speed limit; e.g. 50 to 55 mph; where the rpm gets so low in 6th gear; less than 1,500 rpm.

The trouble with towing "out West" is that there is NOTHING to stop the wind; and it always seems to be windy.

venatic

This is what I do too.

LanceA

Just checked my differential again and it is 3.55. My sail is also 8'8'. Next time I pull her i'm going to try the premium gas to see how that does. Was thinking of putting a cold air intake in as well see if that helps out all. Have had good results with it before in other vehicles.

smokeywren

It's about 300 miles from my house to the kid's house in Austin. I've towed my TT through the Hill Country between Midland and Austin several times, running 87 regular at first, but then one time when running on fumes, I filled up with 91 premium before heading out to Austin. The engine and drivetrain didn't perform any better on premium, but MPG improved more than enough to pay for the increased cost of the gas.

So now I always run premium when towing more than a few miles. My last big trip was dragging a 7x14 enclosed cargo trailer from Midland to Oregon and back in March. The trailer grossed about 6,100 pounds going to Oregon with a trailer packed to the rafters with household goods, plus an overloaded F-150 with a camper shell packed to the rafters too. The trailer weighed 2,000 coming home empty, and with an empty camper shell, but the MPG was the same both ways. So trailer and cargo weights were not factors for MPG, but that big wind sail caused the significantly reduced MPG when towing.

Bigbirt

The stock ecoboost intake is a cold air intake. 'Upgrading' it will not increase your MPG or power. With the money I just saved you, you can fill your gas tank twice - with premium.