when I put ethanol blended gas in my car, the check engine light came on every time I started it up till 3/4 of the tank was gone. My buddy told me to stay away from it cause it burns a little hoter than non-ethanol fuel. So I have and I havent seen the light since. I usually fill up at "shell" 91 octane. cuz on the comercial it says that there high octane fuel was helped developed by BMW, Toyota and Honda.