2. Make sure the air inlet hoses are installed securely.
3. Warm up the engine.
4. Using a vacuum gauge, measure the vacuum in the intake manifold at idle (without load). If the measured value is out of specification, check the following:
- compression in the engine cylinders (see chapter "Mechanical part of the engine")
- check valve
- installation area of each vacuum hose
- throttle body installation area
- fuel injector installation areas
- installation area of the positive crankcase ventilation valve
- intake manifold installation area
Note: Standard vacuum value: -60 kPa (-450 mmHg).