The 35's aren't helping. More wind resistance and weight.
I average combined 14.2 mpg with my popup on all the time and 34" 285-75-17's.
My Smarty on sw#7 default gained me 3/4 mpg over other tunes.
You might want to find a used Smarty Sr. Many are for sale with '06+ users going to EFI Live which isn't available for yours. it'll make the truck a lot more fun to drive. Just watch the go pedal.

Yes I know the 35" tires aren't helping any. I'll be honest I have never had any of my trucks get better than 16 MPG.
My 06 came with the 35's on it and I would hate to go smaller so I guess I'll just have to regear at some point.
Smarty on my truck?? Nope sorry but I'll get out and push before I'll ever run anything made by them. I had some bad run-ins with Bob and a few others and just won't run their junk.
I thought EFI Live was available for my truck now? I guess I misread something somewhere.

Maybe Edge then. My friend has the Edge Evolution I guess on his '05. It seems to be doing the job.
Some guys are running 285-305- 18's. Height without width.
With my early G-56 and 0.79 final drive I've got the equivalent of an auto and 4:10's. With my camper,the gearing works well.
I had one of the earliest Smarty's for the G-56 which produced a CEL. Marco had a fix in 24 hrs. That and updating has been my only contact w/Bob.
An Autocal might be next as I don't have the savvy for the V2.
Once you go that route,the tuner belongs to the truck.

I've had a Edge on my 01 and a H&S Black Maxx on my 08. The 8 would pull the moon back into orbit if it had a chance. That thing was amazing. I had deleted all the emissions crap off of it and it ran so good. The guy who bought it thought I had put new sticks into it because of the power it made.
I really haven't had the funds to mess with my 06 so have just been waiting. My first order is going to be a better tranny. Then I'll move on with the power adders. I really want to supercharge it and then add a turbo to make 700HP.

I recently picked up an edge with attitude for $150 on Craigslist- power setting are more than what I was expecting and the attitude unit is nice- can display 4 different gauges at a time- install was easy. My mileage has increased by 2mpg and that was on 5x5 so I was blowing quite a bit of smoke. It has low boost fueling options which are nice and can change on the fly. be sure you get the unit specific for your model- if there is one as cheap as I found it's a no Brainer!

Those 35s certainly hurt mileage for sure. What is your rear end gear ratio? If your truck is lifted, that too will hurt your fuel mileage.

I'm lucky to get 19 MPG but I attribute that to the 410 rear end

Look at your IAT sensor. 4 wires. Clip the black and red wire and connect (JOIN) the computer end with the blue wire, Do not clip the blue wire. (the blue is your boost reading)
This will give the computer an OHM reading wether the actual intake temp is higher or lower. The hotter the actual air temp the more complete burn = better MPGs but a small power loss..... but the computer defuels when IAT snesor temps read hot. So when you do this, you trick the comp into supplying the same fuel for say 90 air but the motor is actually getting say 140 air which burns all that fuel enstead of blowing it out your tail pipe in the form of black smoke.... equalling better economy but a little less powa.

With the big skins, have you RECALIBRATED the speedo to read the rolling dia ?

2006 ram crew cab diablo programmer 4" magnaflow exhaust turbo back 32" tires air dog 100 1/2 lines and stand pipe IF i keep my foot out of it 21 mpg freeway driving, now with a trailer about 18 mpg