[Jim Allen]

If you do some research (including the study linked above), you will find that, unless the vehicle is tuned for an ethanol blend (basically a flex fuel vehicle), a mileage gain is improbable at best. More than likely, any gains noted will be from other things, not the blended fuel. It's a pretty universal thing... just not as much energy in the fuel and the tuning needs of the engine change with the amount of ethanol which may throw it off more. Some of the cars in the study went excessively lean at WOT, a situation which could be damaging to the engine (of course ecomodder never open the throttle ( : < ). When the vehicle is properly tuned, it can do as well on blended as with straight gas, or nearly so. I'm going to be doing a custom tune on my F-150 in the near future and with blended fuels so prevalent, I may factor an E10 blend into it and see where it takes me.