You may think your car’s exhaust system is designed to only reduce noise, but it's also responsible for reducing harmful emissions from entering the atmosphere. If your muffler and exhaust systems are in good order they not only sound better, but are better for you, your car, and the environment. Your exhaust system starts at the front of your car, right behind your engine. Exhaust manifolds connect to the cylinder heads, where they collect exhaust gases. As the gases move through the exhaust system, they are first analyzed by oxygen sensors. Then refined by the catalytic converter and, finally, muffled by the muffler. Any one of these components can fail and affect everything from your gas mileage to the air you breathe.