I have noticed when I burn e 85 in my 2006 flex fuel 5.3 I consistently get about 20 percent less fuel mileage and it certainly seems to have less power as well.

 

A little hello from France.
Where are you with E85 in your country?
After reading this post I see that your Ethanol is made from corn?
Here in France it is made with sugar beet.
For my part, I have a 2001 Tahoe 5.3 which runs 100% on E85 with a Flexfuel electronic unit, it consumes between 19L and 21L/100km.
It is very interesting for us to use E85 because it is half the price of E10.

Here I would like to have your return after the past 14 years of this post.Sorry for my English it's done with GOOGLE TRANSLATE