What does flex fuel mean on a chevy impala?

Flex fuel on a Chevy Impala means that it is capable of using regular gasoline or a gasoline an ethanol blend that is up to 85% ethanol. This is commonly referred to as E85. There is a sensor that is in Your fuel system that will automatically detect what fuel You use and will change over the map for the ECU to allow it to run with the different type. I recommend always getting the highest octane fuel You can afFord when it is time to gas up though. The higher octane will burn more completely in Your engine and that can reduce carbon buildup and hep Your motor last longer.