For 1990-2009 cars

The air induction system provides air with oxygen for the combustion process. The air cleaner keeps dirt from entering the engine. Outside air is drawn into the air cleaner lower assembly and passes through the air cleaner element. Next the air enters the air cleaner upper assembly and flows through the inlet air duct into the throttle body, and into the intake manifold. Finally the air travels into the cylinder head and through the intake port, ending in the combustion chamber.