Symptom Related Diagnostic Procedures

NOTE: If the vehicle exhibits any of the following symptoms and an emission component is suspect, be sure to visually inspect the following before any tests are performed:
^ Vacuum hoses for leaks, splits, kinks and proper routing.
^ Ignitions wires for cracking, hardness and proper connection at the distributor and sparkplugs.
^ Wiring harnesses for proper routing and connection.

Determine if any fault codes are stored in the Engine Control Module (ECM). Correct any faults indicated before proceding.

SYMPTOM:

ROUGH IDLE
Check:
1. Exhaust Gas Recirculation System (EGR)
2. Positive Crankcase Ventilation System (PCV)
3. Hoses and Connections
4. Idle Air Control Valve

FREQUENT STALLING, WARM ENGINE
Check:
1. EGR System
2. Fuel Pressure Regulator
3. Fuel injector
4. Idle Air Control Valve

ROUGH RUNNING OR MISFIRE
Check:
1. EGR System
2. PCV System
3. Fuel Injector
4. Fuel Pressure Regulator
5. Throttle Position Sensor
6. Manifold Absolute Pressure Sensor

FAILS EMISSION TEST
Check:
1. Catalytic Converter
2. Evaporative Emission Controls
3. EGR System
4. Manifold Absolute Pressure Sensor
5. Heated Oxygen Sensor

LOSS OF POWER
Check:
1. Catalytic Converter
2. EGR System
3. Throttle Body
4. Fuel Supply System
5. Variable Valve Timing Solenoid and Pressure Switches
6. Throttle Position Sensor
7. Manifold Absolute Pressure Sensor