Summary An air cleaner on a multi-point electronic fuel injected engine usually has a different shape from that on a carbureted engine but it serves the same purpose. In many vehicles, the air cleaner is mounted where it can get cool, clean air. This air is then carried to the throttle body by a long, flexible duct. Inside the air cleaner, a filter element of pleated paper filters the air and reduces noise. Some electronically fuel-injected systems have an airflow sensor after the air cleaner element. It accurately measures all air entering the engine and adjusts the air-fuel mixture accordingly. So it’s essential there are no air leaks or it will upset this mixture. There are also many systems that monitor the mixture by using a closed-loop control.