Circuit/System Testing
- Verify none of the following conditions exist:
- The air intake duct system for loose connecting clamps, cracks, or other damage
- A damaged throttle body blade or shaft
- Splits, kinks, or improper connections at the vacuum hoses
- An exhaust gas recirculation (EGR) system leak
- Faulty positive crankcase ventilation (PCV) system operation
- Carbon deposits on the throttle blade-Refer to Throttle Body Inspection and Cleaning .
- Vacuum leaks at the intake manifold, throttle body, and injector O-rings
- If all conditions test normal, test the engine for proper camshaft timing. Refer to Timing Belt Replacement .