Just started driving my 2007 F150 4.6 4x4 and have to say the economy stinks. It has less power and eats more fuel than my '77 F150 with the 400. On two different segments of long distance driving I got 14.68mpg and 14.75 mpg. This is unloaded driving across stretches of eastern Utah and I70 in Colorado. My '77 got a hair over 15 for the same trips. My '64 Dodge with the '86 318 engine got over 20! Now I do agree that power rack and pinion steering and A/C is nice, and it's nice to cut way down on wind noise. The headlights are better too. But the mileage is abysmal. 92,000 miles and it feels almost new, but I never expected to be less than 15 mpg!

R.

 

Gearing could be an issue.... over 15 from a 400 is amazing and I am skeptical. Big fan of that underrated motor, but mileage is not the strong suite...

 

My '97 F150 with a 4.6 got 19-20 mpg on the freeway regularly, as long as I kept it under 70.

Whats the gearing on your '07? Wheel bearings good? Brakes dragging? Transmission hitting overdrive?

 

My daughters 2006 4.6 gets around 19-20 on the highway.. But its not a 4 x 4... I would verify that your not dragging the front end or transfer case.

 

All kinds of problems with vacuum IWE /Get on some dirt and spin the rear tires to see if its in 2wd .

 

Thanks, I'll check up on that. Imagine a system where you have to actively turn the 4WD off. That is a first for me.

R.

 

Does your truck have a lift or leveling kit installed?

 

You are right!

 

It's factory stock, no lift or leveling kit. By the axle codes I have a 3.55 (code #19) open differential.

RE: 400 getting good mileage - I was surprised too but the 3.00 rear and the 30.5" tall tires probably helped. I haven't driven it a lot so it's not a major claim I am making, also I had it jetted way lean for the mountains.

R.