Ok, so I have been driving my truck like a grandma. I still cant seem to get above 14.5 MPG I'm around 9k miles. So, I know it should be better than that. Had EZ installed and didnt change on any level, or when it was off. Anyone got any clues? And I do about 75% highway and 25% city

 

Did you get the reflash at the dealer to fix poor mpg and inaccurate overhead computer readouts? If not, call the dealer and make an appt. There is a TSB about it. Are you hand calculating your MPG? Is your speedo reset for the 35" bfgs (~10% change).

Avg mpg with 265's is ~ 17.5, 35" tires eat 1.5mpg = 16.
14.5*0.10 (speedo adj)=1.5 14.5+1.5=16. Maybe your not that far off...

 

while on this topic, i went to the dealer to have some recalls done, and i asked about this reflash for poor mileage, and they looked at me like i had 3 heads.
is this reflash just for the over head computer, or is it for the ecm to change the way it will run and actually improve mileage???
i Live near Toronto,Canada, so the dealers here are a little slow to whats going on .

 

I have 21,000 miles on my truck and 14.4 is the best I have ever got.
I have had the TSB Flash done and it helped for about 1-1.2 mpg.

I got the same mileage with the factory 235's as I do with the 315's.
The larger tires make up for the 4.10 gears.

I'm still hoping the mileage will get better.

 

I had the flash done too. Same mileage before and after, a solid 14.2-14.5mpg mixed city/freeway.

 

I just had the re-flash done and I am seeing about a 1 MPG change from 15 to 16. Seems to have better grunt from start and I have not put the Airaid system back on yet!!!

 

I have had the flash about a month after i got the truck in October. Havent changed the tires out yet so that is with the stock on. So go from there.

 

PThree, couple of thoughts. First, have you had the speedo recalibrated for the 315's or do you take the extra approx. 10% into consideration. Also, is your mileage no. hand calc. or from the o-head? If from the o-head, it has a good chance of not being accurate. Finally, you have the auto so that will hurt somewhat and also fairly low miles on the engine still. fwiw

 

autos will now get a little better FE on the highway due to the better (numberically lower) overdrive ratio in the 48RE.

The re-flash both changes the ECM cal to improve FE and changes the information sent to the overhead to imrove accuracy.

You must hand calculate to be accurate. You'll have to reset your overhead in order to compare tank to tank overhead vs. hand calculated.

Bigger tires should help on hwy because of the numerically lower final drive ratio, but hurt city FE numbers due to the increased rolling resistance of the wider tires.

You will have to have the truck reprogrammed by the dealer for the bigger tires.

 

I HAVENT SWITCHED TIRES YET!!! LOL ok now that, that is done. I have had the flash. I do calculate by hand. The overhead says 17 sometimes and others 20. I reset it every fill up. But everytime the hand calc. comes out the same to around 14.5-15. This is a short bed quad cab 1 ton. I really dont think i should be getting this crappy of mileage. Air filter is fine and when i change it, i will go to the AFE. But other than that of the EZ and Leveling kit it is stock along witha EGT gauge that goes above 1400 when i floor it. Normally runs around 650-700 at 65 mph. Someone help

 

Running stock. Had reflash done about a month ago. Made the overhead accurate against hand calc. Mileage went up from 16.4 to 18.3. Mostly country driving, mixed with a small amount of city and a small amount of Interstate.

 

any body know what the reflash is called???
i posted before, the dealer i went to looked at like i had 3 heads.
they never heard of such a thing, but i would like to get it done, but i need to be armed with something other then "i need a reflash"
thanks

 

Drive it a little harder, My dads was getting about the same mileage and he started driving it like normal and the mpg actually went up go figure...

 

I believe it's the tsb-037-004. A buddy just got his done and got 2mpg increase right away. Another buddy called his dealer and they didn't know what he was talking about. I made him call back and talk to the head nuts and SHE took care of him. He is getting 1.5 better.
They both said that their truck runs better.

Kris

 

With nearly 500 miles on my new truck, I still have 1/8 of a tank (dealer filled it before I drove away). The overhead says 18.1 and I think that will be very close. FE has dropped do to frequent stop and go errand running today, not to mention puching it when trying to get around mentally challanged drivers Man, does this '05 JUMP when you stomp on the go button. YEEHAW! A lot more fun than my '04HO was!