Flex fuel

85% Ethanol and 15% gasoline. Guaranteed to ruin your engine!!! If you have a Flex fuel engine give it a try. Your fuel economy will go down so you will have to calculate the cost per mile to see if it really is cheaper than E10 or straight gasoline.

Flex fuel vehicles can run on regular unleaded gasoline at any octane rating such as 85,87,89,91, and 93. They can also use varying concentrations of ethanol based fuel such as E-10 through E-85. As F_O_R pointed out E-85 is cheaper per gallon, but you will get less fuel mileage with it so you need to figure the cost per mile on using it to see if it is financially worth the trouble.

FlexFuel is like running your car off 85% vodka and 15% gas. It gives you more ~20% horsepower and torque because it's 107 octane vs. 87 octane in gasoline. Usually, the cost per mile is the same or less than gasoline. But, I'll stop for a 5 minute fuel up more often for more power and it's buying your fuel from farmers instead of Big Oil. Fracking is poisoning our water.

Is flex fuel good to use in a 2008 ford F-150 XLT

Stopped working at 2000 miles. Used to completely turn engine off at red lights and back on when gas pedal touched, now just runs continuously. Is this normal?