Frankly, standardization is often the only option given the limits of a universal technology standard. 1  1. Standardization lag: It takes time to understand a problem domain well enough to make a proper standard.
A flexible-fuel vehicle (FFV) or dual-fuel vehicle (colloquially called a flex-fuel vehicle) is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol or methanol fuel, and both fuels are stored in the same common tank.
Flex fuel capability. If you fill up with e85 or add to a tank of regular you need to drive the truck for at least 11 miles for it to  learn the new fuel that's in the engine. Search this topic and you will finds tons of info about this.