Curious as to what others are getting for mpg in there 6.2's with the 8speed. I have 3.23 rearend and am contemplating swapping to 3.42+ gears.
Also some opinions on what a tune has done for yours so far?

 

I get about 16 mpg on a tuned 6.2 -8 speed, with 4 cyl mode off and 3.42 gears, 4wd on 20"s
I drive it like it is stolen.

If I were to change gears, I'd go to 3.73's

Why do you want to change gears, 2wd or 4wd

 

So your 16mpg is that hwy?
I can't help but feel my 12' 6.2 3.73 geared had more pep above 3k rpms anyways. I like this new motor a lot more under 3k plus I've gotten 18.5-20.2 hwy avg's compared to my older 6.2 getting best of 16.5 haha
Idk if more rpms but less load would create easier to obtain higher mpg compared to less rpm but more load.
also wanting a taller tire for winter time etc so I figured more gearing would help over come that plus give me more feel of power in summer on reg tires.

 

I have the max trailering package so I have 3.42's with the 8l90. My running 400 mile average is always 16-17mpg. That is commuting about 14 miles on the highway with cruise @ 78mph and an additional 4 more in city. Just long highway trips I avg 18-19 @ 78mph. I also use the full potential of the 6.2 when I can so I'm sure I could eek out a bit more if I babied it.

 

That's not as bad as I thought. Stock tires?
How do you like the shifting in town?

 

Stock tires.

The 2-3 shift is kinda harsh some times, but the rest of them is fine. It took me a bit to find a good pedal pressure to not chirp the tires, but not take off slow.

 

My mileage is all urban,
A higher numerical gear will would only make a small increase in fuel use, imho.

 

I cant help but HOPE a tune on these would help MPG and power across the board the same as any other year truck.

16-18 average for a weeks worth of gas isn't to bad, though I would hope it would be more closer to 18 steady. Remember we have big trucks with big motors. We didn't buy these babies to cheap out at the pumps lol.

Ive noticed babying my 2009 truck does increase mpg by about .7 - 1 mpg average per tank. But man its annoying as hell to not use remote start and keep the rpm under 2500.

 

I'm hoping a tune helps as well haha. I have a Diablo intune sitting on the shelf. I decided to wait a few more miles before installing it.
Agreed they are big trucks and we opted for the biggest motor. So far I'm impressed with the mileage. Wasn't impressed that pulling a empty trailer got me the same mpg as pulling same trailer loaded haha. But 12-13mpg both ways loaded down wasn't a huge let down. Heck my work truck empty gets that or worse(11 3/4 ton 6.0 gasser)

 

I have a 4wd and had an average of 21mpg on a 500 mile trip. The best I ever got was 24mpg and that was cruzing at 55mph in Ft. Walton Florida.