boost is the pressure the turbo builds. And im not really going to argue about weather more or less boost burns fuel or not but for my truck it likes to have about 10psi to get good millage. my 12v like to have about the same and the semi i drive likes to stay about 15psi.

 

the basics.... tire pressure to spec on the inside of the driver door not the sidewall of tire. intake and exhaust breathing good. keep off the pedal, suspension check, alignment check, fuel filter, eco tune

 

I just scan read over this, so forgive me if this has been offered: have you hooked up to the OBDII port under the dash on the driver's side to check for fault codes? 13mpg on a stock 6.0 is ***! I live at 4000ft and got 14~15 stock on 33s in town. I get 13 on 35s right now. However, when I go to a lower elevation, Vegas (2000ft) or Phoenix (1300ft) I get mucho bettero mileage! Like 15 in town on 35s.

But I digress, check your codes, THEN worry about upgrades.

 

i just picked up my 06 350 extended cab, 8ft bed with 80k on it
first three tanks mostly highway cruising 60-70 i was consistant with 14.9 doing the math
i removed the muffler, 15.7
i removed the cat 16.9
i dont drive like a granny but im not out to win any races either.

i just received my custom tunes for the sct from sinister-diesel. i got the eco, towing, and street.
i ordered the sct for the promise of the eco tune getting 3-4 mpgs more on average.
figured if i get atleast 2 i would be happy. that would get me close to twenty on the high way! (more than my tacoma got)
btw i too let the rpms go up and keep the boost down. in heavy traffic, i will activate tow mode to let the engine rev more. less labor and lower boost.

stock suspension and wheels with 3.73

 

No code errors this truck just get 13.5 -13.8 and i cant do any better without changing something tire pressure stays good where they should be

 

IS "where they should be" the psi that puts the best tread contact down, or the MAX PSI quoted on the sidewall.

Yeah, yeah, I'm highjacking, but this brought up a point: chalk. Scrub some chalk across your tires and see whats left when it scrubs off, chalk on the outside indicates too much psi for even tread wear. This psi is going to change when the same tire is mounted on different width rims.

I burned up the center of a few 365/65/16 Toyos running them at 50~55psi that still had meat on the shoulders before this was knowledge was laid on me.

Back on point, what is the altitude where you live? As stated earlier, my mpg is better at 1300ft than it is at 4000ft.

 

inside door psi not sidewall
i live in ohio
tires wearing very nice (even)

 

Pressure on sidewalk will probably get you better mileage, even though you may give up some tread life.

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Run what you want, but if you do the chalk trick with an empty truck, be sure to recheck before you go to far with a heavy load. Just thought that might be easy to overlook.

 

i need all the help i can get thank you

 

These threads always kill me...

I will say, I have found that some good tuning will allow you to drive like an a-hole with a LOT more power than stock, and still achieve roughly the same mileage as before, but have a lot more fun doing it. I wouldn't really expect any gains, though it's possible to get some. It's better to be happily surprised than it is to be let down. Mod for power, not mileage. If you get more mileage, just be really happy.

We still don't know what cab/bed configuration this truck is do we? What trans? (auto or manual)? 4x4/2x4???