My 08 Hemi quadcab is averaging 18mpg in mixed driving. It will be even better when the winter blend gas goes away.
Right now my only mods are a K&N drop in filter, Airaid MIT pipe (no effect on mileage), soft TruXedo bed cover and a Diablosport Predator running 93 octane fuel and setting with the MDS turned on.

Due to rigorous testing, I have determined that my Magnaflow cat-back, does outflow the stock set-up quite a bit. Enough, in fact that although it makes more hp upstairs, it actually lost enough backpressure to cost a bit of low end torque and was hurting my mileage by over .5mpg. I removed it to try to pinpoint a bearing noise (front hub bearing) and noticed the MPG increase with no other mod or change in driving habit.

My window sticker says my truck should get 13 city/19hwy. On straight hwy trips, I get 22-24 depending on the terrain.

No full size truck is going to get great mileage. They are heavy and slice thru the wind like high rise building. I can tell you that my Ram has 75 more hp than my 01 F150 5.4L did and gets much better mileage and will out pull it by a bunch.

Ford advertises the high mpg's, but they do not tell you the truck configuration. I am quite sure that the mileage claims are for a std cab, short bed, 2wd lightest available truck with that engine.
I bought my 08 new. The only issues I have had in 45K miles is that both front hub bearings have failed. I am guessing that they got a bad batch of bearings from their supplier because this is not a common issue on trucks under 120K miles. I love the truck, I drive it 72miles round trip to work most days unless my wife is off, then I will drive her 35mpg Caliber
My only real complaint is with the factory shocks. They are way too soft. Bilstiens fixed that problem!!

I see that the link no longer works. Did you buy the truck?

 

thanks again for the replies fellows.i have not bought the truck,still stringing the salesman along.sounds like a better deal all the time though.