What is the effect of a worn exhaust?

A worn exhaust system can significantly impact a vehicle's performance and emissions. When the exhaust system is worn, it often results in a reduced ability to filter out harmful fumes, which leads to an increase in exhaust emissions that can harm the environment and affect air quality. This deterioration can also cause an increase in engine noise, as the exhaust gases may escape the system more freely than intended, leading to a louder operation.

The correct answer underscores the critical role that the exhaust system plays not only in controlling emissions but also in maintaining the overall sound levels of the vehicle. A well-functioning exhaust system helps ensure a quieter ride while minimizing the release of pollutants. In contrast, other outcomes such as increased fuel efficiency, improved vehicle performance, or no effect at all do not accurately depict the consequences of having a worn exhaust. These options misrepresent the crucial role of the exhaust system in both vehicle operation and environmental considerations.