The exhaust system is responsible for directing exhaust gases away from the engine and toward the tailpipe. It includes components like the exhaust manifold, catalytic converter, O2 sensors, exhaust pipes, muffler, resonator, and tailpipe, as well as other miscellaneous parts like gaskets, heat shields, and hangers. If the exhaust system leaks, it can expose you to high levels of carbon monoxide. A obstructed exhaust system can also create back pressure, effectively choking the engine and resulting in a series of performance issues.