Manifold pressure is the pressure of the air inside which component?

• A. Inlet manifold
• B. Exhaust manifold
• C. Crankcase
• D. Air filter housing

Answer: (A)

Manifold pressure refers to the pressure inside the intake manifold—the plenum that distributes air to the cylinders after it has passed through the throttle. This pressure reflects how much air the engine is drawing at a given throttle opening and RPM, so it’s a key indicator of engine load and power output. It is not the pressure in the exhaust system, the crankcase, or the air filter housing (which sits upstream of the throttle and is typically near ambient pressure). Therefore, the pressure inside the inlet manifold is the correct concept.