What symptom might occur if the air filter is dirty?

A dirty air filter can significantly impact engine performance in multiple ways. When the air filter is clogged with dirt and debris, it restricts the airflow to the engine. This reduced airflow can lead to a number of symptoms, including:

• Reduced Engine Power: The engine requires a specific air-to-fuel mixture to operate efficiently. When the air filter is dirty, less air enters the engine, leading to a leaner mixture that can reduce overall power output.

• Increased Fuel Consumption: With less air available for combustion, the engine may compensate by injecting more fuel to maintain performance. This can result in higher fuel consumption as the engine works harder to overcome the lack of optimal air supply.

• Unstable Idle: An inadequate air supply can cause irregular airflow into the engine, leading to unstable or rough idling. This happens because the engine control module struggles to maintain the right combustion process with insufficient air.

Considering these factors, the correct answer highlights that all of these symptoms can occur when an air filter is dirty, making it essential to maintain a clean air filter for optimal engine performance.