Flashed today...O/H reads about 2.5mpg higher...was reading about 1mpg low before, so if correct, should be up 1.5. Truck sounds the same, but power seems to come on quicker. Used to have the power drop off at 27-2800 RPM in WOT accel in lower gears.(2-4)(defueling?). Now powers all the way up.

 

I'm seeing a 1.4 mpg improvement in city driving (15.4 to 16.8) and the numbers keep on climbing...

 

Thanks for the advice guys, I'm going tothe dealer at 9:00 this morning. I'll talk to them about it again then.

 

what is this TSB or flash? is it in print somewhere, how do you find out, ask a dealer or what?

 

The flash is yielding a net gain of approx 1 mpg on the overhead. It's showing a gain of 2 mpg but the overhead was 1 mpg low before the flash. So assuming the overhead is now accurate, I'm getting a net gain of 1 mpg.

I haven't done any hand calc yet.

Jury is still out on power change.

No sound change.

Shifting hasn't seemed to change but I pull a 5000lb trailer all the time and maybe that hides any change in the shifting pattern.

 

Mine is showing exactly 1mpg higher than actual now after the flash.
It was only .2mpg off before. But I am getting 1 mpg better mileage also....

 

I had mine done this morning. I had an appointment, went in, described white smoke (which I actually hardly ever have) and poor mileage. I handed her a copy of the TSB, and an hour later, I was done.

Invoice only states "ck on TSB 18-037-04". NO sticker anywhere under the hood.

Now, on the way home from the dealer, 35 miles of mixed high speed (70+) driving, and stop and go, I was getting mid-14s, according to the overhead. This is probably 1-1.5 higher than before with that type of driving. I can't tell ANY difference in performance, truck feels just as strong as before. The only difference, and for the better, is that the transmission shifts MUCH smoother into overdrive than before - no more of that nasty "wwwhoooomp".

It's going to take a good week or so of my normal 11-mile stop-and-stop commute before I really will be able to get any meaningful mileage data.

My computer also was very accurate before - within 0.2. If it's still as accurate, I'm happy.

 

had mine done yesterday reset the overhead at the dealer the 8 mile drive home is a 1400 foot vertical climb the overhead read 18.7 the best i ever got on that trip before was 14.4 overall previous to the tsb the avg was about 18mpg seems much more powerful than before i was squeeling tires and not even trying to.