What maintenance task can help improve fuel efficiency in a vehicle?

Regular oil changes play a crucial role in maintaining a vehicle's engine performance and can significantly impact fuel efficiency. Engine oil lubricates the moving parts of the engine, reducing friction and allowing it to run smoothly. Over time, oil can degrade and become contaminated, leading to increased engine friction and reduced performance, which in turn can cause the vehicle to consume more fuel.

When an engine is properly lubricated with clean oil, it operates more efficiently, allowing for better fuel economy. This is especially important because an engine that is not running at its optimal level can waste energy and fuel. Changing the oil regularly as per the manufacturer's recommendations helps ensure the vehicle runs efficiently, directly contributing to improved fuel efficiency.

The other options, while they may have their own benefits, do not directly correlate with maintenance practices that improve fuel efficiency in the same straightforward manner as regular oil changes. For instance, using premium fuel could enhance performance in high-performance vehicles but does not necessarily improve fuel efficiency in all cases. Washing the exterior can improve the aesthetic appeal but does not affect fuel economy, and changing tires typically pertains to safety and traction rather than efficiency unless one is switching to more fuel-efficient tires specifically designed for that purpose.