Your vehicle has many different complex parts in its mechanical system. One component that you may not be aware of until something goes wrong is the engine air filter. The engine air filter is found in cars with gasoline or diesel engines. This small part plays a large role in your car's performance, fuel economy, and overall health. Air filters can be made of various materials, including cotton, fiber, and paper. While their material composition may vary, they have the same role in all vehicles. The engine air filter ensures that sufficient volumes of air can reach the engine.