Since the F-150 doesn't currently offer a V-6 power plant, will the Ecoboost provide 25% better economy than the 5.4L or the 4.6L 3v or the old 4.6L workhorse.

So, well take the worst case scenario and use the FX4 with the 5.4L and 3.73 axle rated at 14 city and 18 hwy.

By thier numbers, that becomes 17.5 city and 22.5 hwy.

Or if you use a 4x2 with the 3.15 axle rated at 21 hwy, you should jump to 26.25.

The Taurus and Flex aren't even rated to achieve these numbers, how will a 5000 lb 4x2 truck do it?

I think the 5.0L is going to be the way to go.

Tim