In your vehicle’s exhaust system, the manifold collects harmful emissions produced by the engine during the combustion process. The exhaust manifold is the first compartment to receive these gases from the engine’s cylinders. The manifold collects the harmful gases produced during the combustion process. The manifold contains an oxygen sensor that tells the engine control computer to increase or decrease the amount of oxygen in the fuel and air mixture assembled during the combustion process. After the leftover gases are collected in the manifold, the manifold funnels these gases into the rest of the exhaust system. Over time, this process of heating and cooling can eventually take its toll on the manifold.