How does a failing ignition coil affect engine performance?

A failing ignition coil can significantly impact engine performance in a couple of crucial ways. When the ignition coil malfunctions, it may not provide the necessary voltage to create a strong spark at the spark plugs. This inadequate sparking can lead to incomplete combustion of the air-fuel mixture inside the engine cylinders.

As a result, one primary outcome is a reduction in fuel efficiency. The engine requires a proper air-fuel mixture to operate efficiently. If the ignition coil isn't functioning correctly, it will use more fuel to compensate for the lost power, leading to higher fuel consumption.

Furthermore, incomplete combustion due to a weak spark will also increase exhaust emissions. When fuel doesn't burn completely, it generates more unburned hydrocarbons and other pollutants that are released into the atmosphere, thereby worsening the engine's environmental impact.

Therefore, addressing the problem quickly is essential not just for maintaining fuel efficiency but also for adhering to emissions regulations. This highlights why the most comprehensive answer includes the impact on both fuel efficiency and exhaust emissions.