Diesel and gasoline are both fossil fuels used to power engines. However, they differ in composition and performance. Diesel is a heavier fuel, made from crude oil, that contains more energy than gasoline, and is used in larger vehicles, such as trucks, buses, and construction equipment. Diesel engines can also be more efficient than gasoline engines, as they produce more power with less fuel. Gasoline is a lighter fuel, made from petroleum, that is used in smaller engines, such as those found in cars. Gasoline engines are not as efficient as diesel engines, but they are typically faster and provide better acceleration than diesel engines.