Well since there hasn't been an abundance of response, I'll give another bump and say that I am 2wd and have a quad cab, but I get a minimum of 19 or 20 mpg hwy. If I cruise at 65mph I've done as good as 22.5mpg avg on a trip.
When I drove from Norfolk, Va to Pheonix, AZ in July, I took US-58 to I-95 to I-40, through TN mind you, I averaged 19mpg there. 13.5 on the way back with a trailer full of household goods. I avg about 14 mpg here in the greater Hampton Roads area of VA.
Mine rarely sees the hwy. I get about 11 in town, and the best ive gotten on the hwy is 15, and that was pulling a trailer. Its only been on the hwy twice, and both times i was either pulling a trailer, or had a bed full of junk.
When the 2009 first came out the reviews mostly claimed that there is hardly any difference so why not get the 5.7. I think by reading concerns and folks personal reflections on mpg it is gearing, Cab size 2 or 4 wheel drive that makes the difference. Also driving habits will reflect results. Some seem to get really good mpg will others say with the same truck that is not possible. I am happy with my truck 11, 12 driving in traffic lights and stop go traffic makes a great difference highway driving mostly 18, 19, have seen 21 on the evic.
I get about 18 ltr per 100km in mixed driving and about 13.5 on the hywy. Avaraged 16.5 on a moose hunt with the truck full of gear and pulling a trailer with an ATV on it. I am happy with my mpg and the power available from my engine its the price per ltr on the gas pump thats the problem
I have an 09 4x4 4.7l with the 3.92 gears. I get about 14 in town(I have a heavy foot off of stoplights and such), and I get about 20-21 on highway between 65mph-75mph. My highest was 24.7 at 65mph over a 200 mile trip