No MPG Boost tune?

[2004z71]

am i correct in understanding that i dont get an "MPG boost tune" because my truck is 2004?

so far i am down in MPG... a lot...

[mikel]

Yeah, wasnt much to improve on them like the newer trucks with AFM...but nothing in the tune will cause a drop.

Was your speedo off before you loaded the tune?
if so, you can compare MPGs before and after correcting the speedo...

[2004z71]

The 87 tune killed my mpg


Stock gears.
I changed to 285/75R16 tires immediately.
Stock was 265/75R16

When i do my MPG id add 10% to the odometer and cross reference that number against google maps.

The Diablo tuner now gets me 16mpg highway....
My 1987 4x4 got that

I uninstalled the 87 tune and just did the tire size and transmission shift mods. So we will see.

$360 to adjust tire size and change shift points.....

And this morning the speedometer was 5mph off. according to the school zone radar sign

[mikel]

I dont think you can properly correlate the MPGs before and after the tire size change in that manner.

[2004z71]

No, im saying these tires have been on the truck since i have owned it.

It got 17 now it gets 12.

I uninstalled the tune so soon we will know of its back to 17.

Point is... it killed my millage.
Probably gonna return it unless i can get a tune that works

[06MonteSS]

well, the preset canned tunes do not change any airflow or fueling settings at all... so the tune is not causing it really... plus, after installing a tune, everything gets reset and it takes days/150+ miles to be put on for everything to get relearned by the PCM and settle back in again.. and the mileage info in the DIC will not be correct for a while...

[2004z71]

This was done over 2 tanks of fuel.
Usually a tank lasts me over 300miles (without actually going empty)
The diablo tune drained 22 gallons in almost 200 miles.
So the MPG gains are a lie. Fake news lol
That was the whole reason i bought this thing.

Now its got a problem with the brakes where it pulls right..... into the gas station.