Circuit/System Testing
- Operate the engine within the conditions listed in the Freeze Frame Failure Records.
- A current misfire should not be indicated.
- If a single cylinder Current Misfire is indicated, inspect the following components of the affected cylinder for proper operation:
- The ignition coil-Refer to Electronic Ignition (EI) System Diagnosis .
- The spark plug-Refer to Spark Plug Inspection .
- The fuel injector-Refer to Fuel System Diagnosis
.
- If there is still a single cylinder misfire, refer to Symptoms - Engine Mechanical .
- If more than one cylinder is randomly misfiring, inspect the following components condition and operation:
- The vacuum hoses and seals-Refer to Evaporative Emissions (EVAP) Hose Routing Diagram .
- The throttle body and intake manifold
- The crankcase ventilation system-Refer to Crankcase Ventilation System Inspection/Diagnosis .
- The ECM grounds
- The exhaust system-Refer to Restricted Exhaust .
- The fuel-Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- The spark plugs-Refer to Spark Plug Inspection
.
- If more than 1 cylinder is still misfiring, refer to Symptoms - Engine Mechanical