Intake Manifold Vacuum Inspection

Verify air intake hoses are installed properly.
Start the engine and run at idle.
Measure the manifold vacuum using a vacuum gauge.
- If not as specified, inspect the following.
  - Air suction at:
    TB installation point
    
    Intake manifold installation point
    
    PCV valve installation point
  - Fuel injector insulator
  - Accelerator cable free play
  - Engine compression (See COMPRESSION INSPECTION .)
NOTE:
- Air suction can be located by engine speed change when lubricant is sprayed on the area where suction is occurring.
Specification

More than 60 kPa {450 mmHg, 18 inHg}

Fig 1: Measuring Manifold Vacuum
Courtesy of MAZDA MOTORS CORP.