The amount of fuel efficiency loss depends on the percentage of ethanol in the gasohol blend. For example, E10 gasohol, which contains 10% ethanol, has a fuel efficiency that is about 3% lower than plain gasoline. E85 gasohol, which contains 85% ethanol, has a fuel efficiency that is about 25% lower than plain gasoline.
In addition to reducing fuel efficiency, gasohol can also cause other problems, such as engine damage and increased emissions. As a result, it is important to weigh the pros and cons of using gasohol before deciding whether or not to use it in your car.