Component Tests and General Diagnostics

Intake Manifold Vacuum Inspection
1. Verify air intake hoses are installed properly.
2. Start the engine and run it at idle.
3. Measure the manifold vacuum using a vacuum gauge.
- If not as specified, inspect following:
- Air suction at throttle body, intake manifold and PCV valve installation points
- EGR valve (struck open)
- Fuel injector insulator
- Engine compression

NOTE: Air suction can be located by engine speed change when lubricant is sprayed on the area where suction occurs.