my truck is stock and empty and driving sane i get 650 - 750 miles out of a tank
i use diesel clean with cetane boost every tank(in the grey bottle). and my rig aint no reg cab short box

on secret is to keep your mass air flow sensor clean i use a good carb cleaner i do that every oil change. make sure it evaporates and doesn't leave any deposits

 

oh yeah, the MAF is very important to keep clean,

it can be a real hassle if you have an oiled aftermarket filter. it can cover the sensors with oil and your MAF will give false readings back to the ECM. End result extreme turbo lag and loss of mpg, and not as responsive.

 

have a tube that keeps coming off like mine i need to find a new intake tube that is either longer or get new boots that are longer i have to check mine almost everyday. you could try what this guy does its called hypermileage i saw a clip on a show about this once they used a that little Pontiac sports car

 

24 is really pushing it. 27?? NO WAY. The only way that happened is that he was driving down a mountain. I average 21.5 on the freeway at 75 mph and 15 in town. I sit in traffic for 2 hours a day so my in town mileage is going to be low. 650-750 on a 26 gallon tank. NOT HARDLY. You're trying to tell us that your getting 25-29 mpg??? Might wanna call GM...you've just performed a miracle.

 

Not to jump on the bandwagon, but I have to agree. Even with stock tires, 27 is not going to happen. Double check and hand calc your #'s. If you found a way to get 27 with real world driving, you will be wealthy very soon when you sell your secret.

 

how many of you every driven at 55mph for a long time, i know it hard, but it could increase mpg.

I just cant live that slow to find out for myself

 

Just a note:
A while back, some people were jacking around with high MPG tunes and saw increadable numbers BUT melted a few pistons in the mean time Just an FYI.......

 

im good with 20, dont need more than that myself

 

My 03 LB7 gets 22-24 mpg with about 20% in town driving at 70-75 mph. Pulling a 40 ft trailer empty is 15-16 and loaded grossed out at 45k it gets just over 10.
I have 5in straight exhaust and other than that I have no other upgrades. I do use a additive called Howes Meaner Cleaner, which I swear by. Maybe the 6-spd helps out a little too.

 

Maybe he has a long bed with the 34 gal tank