This is probably a useless thread but I have been trying to figure this out. I have owned my Tacoma for about 3 years now and have always averaged 15-17 mpg. I have never gotten over 17mpg and usually unless im driving very easy i don't get 17 mpg. But the other day I had just cleaned my air filter and put it back in and i usually fill up at a gas station that has 10% ethanol. But that day I filled up at an older station, they had a sign out front that said no ethanol plus the gas we cheaper so i filled up there. With this tank i averaged 17.99 mpg. The only thing that threw me was that i guess i didn't lock my air box lid down because when I went to change my oil it was open. So after saying all that my question is do you get better gas mileage with ethanol free gas or was it because i had less restriction for my air flow?
Im leaning towards better gas mileage with the ethanol free gas because i filled up at the same station this weekend before we went 4wheeling and my gas mileage was noticeable better hauling the trailer then it usually is.