Intake-Air System: Notes

The intake-air system is composed of the following parts:

• The fresh-air duct channels fresh air to the air cleaner and is equipped with a resonance chamber to reduce induction noise.
• The air cleaner removes dust and particles to prevent engine contamination.
• The mass air flow (MAF) sensor measures the intake air volume.
• The air hose directs fresh air to the throttle body.
• The throttle body controls the overall quantity of air provided to the engine and is equipped with an air adjusting screw (AAS) for the idle speed adjustment.
• The idle air control (IAC) valve directs by-pass air to the throttle body to maintain the proper engine idle speed under various conditions. It is controlled by the powertrain control module (PCM).
• The intake manifold distributes the fresh air into the each cylinder. It is equipped with the variable resonance induction system (VRIS) shutter valve for improved engine performance.