Intake Manifold: Testing and Inspection
VACUUM MEASUREMENT1) Warm-up the engine.
2) Disconnect the vacuum hose and install the vacuum gauge to the hose fitting on the manifold.
3) Keep the engine at the idle speed and read the vacuum gauge indication. By observing the gauge needle movement, the internal condition of the engine can be diagnosed as described below.
Vacuum pressure (at idling, A/C "OFF"):
Less than - 60.0 kPa
-450 mmHg, - 17.72 inHg)