What is a common sign of a worn exhaust?

A common sign of a worn exhaust is its reduced effectiveness in filtering exhaust fumes. The exhaust system is designed to direct harmful gases away from the engine and reduce emissions. When the exhaust becomes worn or damaged, it can lead to leaks or other issues that compromise its ability to filter these gases effectively. As a result, more pollutants may be released into the environment, and the vehicle may not meet emissions standards, which can also trigger warning lights on the dashboard.

The other options, while they may relate to exhaust system issues, do not directly indicate a problem associated with the physical condition of the exhaust system itself. Decreased fuel economy can occur for various reasons beyond just the exhaust, increased engine temperature might suggest cooling system issues, and improved acceleration would not align with what happens when the exhaust is worn; typically, performance would decline. Thus, the correct answer focuses specifically on the filtration effectiveness of the exhaust system.