Welcome, Michael!
Please forgive me for taking the liberty to edit your first post - the link wasn't posted correctly.
(For future reference, you can't simply cut and paste them into the body of a post here - you have to use the chain icon in the toolbar above the text area. Yes, it's arcane, but we do things differently here, and I suspect different is what you're looking for)
Ahhh, ethanol. that was (and remains) a scam and a half as far as I'm concerned. so why do i think it's a scam?
Yes, it costs less to fill a tank with e85 but you don't get the mileage you would with gasoline, or even e10 gasoline. why? ethanol doesn't have the energy density that gasoline does.
you might think you're paying less at the pump, but when you do the math, you're not getting any sort/much of a deal in terms of cost per mile vs gasoline. So ethanol is false economy
and then there's the enviro impact of making the ethanol fuel stock...but you're from corn country - I'm sure you have friends/family/neighbours who rely on corn for their living, so you think in buying ethanol fuels, you're helping them and the economy. that may be the case, but not to the extent you might think (I suspect you're keeping certain companies stock prices and dividends and tax revenues up for certain parties, but unless you own stock or benefit significantly from the taxes, I bet you're worse off). again, false economy, ultimately draining your pockets just a tad bit more.
I admit, I haven't read the paper, but it's over a decade old and I'm not sure carmakers are selling flex fuel vehicles anymore. they've come up with other ways to get more for less out of a fuel tank.
For you and tour truck, I would advise you stick to gasoline (premium, ethanol-free if possible), and get your truck grooved and snake oiled, but make sure it works as the factory intended before so the computer needs to take a fresh look at things and make the adjustments our process is capable of inspiring it to make. From there, we can talk about optimising your ignition and and a bunch of other optimisations/mods to let you get more distance out of what you put in the gas tank.
For now - changing your plug gap from 54mm (that's a 2" gap...was it 0.054" perhaps"?) to 62mm (uhhh, 0.062" I hope, not 2.5") got you an initial bump in mileage of 1mpg.
what happened then? the oxygen sensor(s) saw too much oxygen in the exhaust and added fuel back to compensate...your mileage might swing back higher in time, but i would guess you'll have to take more control of the computer- and that's not as difficult as it sounds, or as expensive. However - see what happens if you take the gap up just a wee bit more. the Ford Ranger I used to drive was able to run quite normally with a spark gap in the 0.066" or slightly higher as I recall, and the factory gap was 0.044"
