Does a car or truck have to be specifally marked as flex fuel to use ethonal or is it safe to use in most modern vehicles. My wife once had a 2002 Taurus that was flex fuel tho we never used ethonal because none of our local stations had it at the time. Now some of them have it and neither of us have flex fuel vehicles. Would it be safe to burn in my 04 F150 4x4 and her 06 Explorer? If so how does it compare to gasoline? I know its supposed to burn cleaner and is made from corn but if it doesn't cost less and/or last longer then I don't see the point?

 

Not over 15% ethanol if not a flex fuel. They are just not designed for the fuel mixture needed. It takes more going into the combustion chamber or U lean out. Using say a gallon as an engine cleaner, gently usage.