well, whose truck got 8-9mph?!!

Most gearing is rated for 31.5 inch tires. If you are running 4.10 and have 35's on your truck you have effectively changed your gearing to around 3.73.

I'm leaving in the morning for Destin then hauling it over to Cumberland. Shouldn't be too long till 10k. Everything smooth with your latest project Jeff?

I just put an edge products juice platinum with attitude box in my 06 6.0 ford dually, and first tank got 3 mpg better than stock.

Sorry about the misinformation earlier, there are tuners out now for the 08 trucks.

It is amazing that Ford's stock programming only gets me 12 mpg average over 100 gallons, while an aftermarket chip company can make a program, use the same engine, give it more horsepower, and produce better fuel mileage!

Something is wrong with this picture!

If you go with a chip or tuner, make sure you install an exhaust gas temp guage (pyrometer), or you will roast your turbo.

I drive 100 miles each way to work and back daily for work. I was tired of having to stop for fuel every other day, so i installed an aftermarket fuel tank in the bed of the truck. The tank sits flush with the bed, is made of alum diamond plate, and the top 8" of the tank is a tool box. Looking at the tank, everyone thinks it is a tool box, but it holds 75 gallons of diesel, and is gravity fed to the stock tank.

My fuel guage stays on full for approx 1000 miles, and when it starts to move, I know that the tank is empty, and I still have the factory tank to burn, for another 300 or so miles.

Filling it up takes approx 90 gallons for a cost of 270.00. I stop for fuel every 1200 miles.

lets see:
everyone wants bigger badder trucks to pull bigger badder loads at faster and faster speeds with more and more hp yet magically want them to get better milage??
physics= takes fuel to make power, the more power and the bigger the vehicle+load+speed the more fuel it takes.
Add in huge aftermarket tires+rims+4wd and sky high lift kits and it only gets worse..
Same reason reliabilty is not what it once was either, the more power they squeeze out of them the more toll it takes on the life of the engine..
Then again if you have the bank to replace them every couple years I guess thats not an issue.

Macattak

The 08 has factory probes in the exhaust, and will kill fuel if EGT's get high - someone finally built in a failsafe

I chipped a 2004 6.0 and it really helps power but my experience is that it doesn't affect fuel milage very much, certainly not while towing. Also, semis dont do anywhere near as well.