Circuit/System Testing

Inspect the air intake system for the following:
- Damage, restriction, or modification
- Dirty or deteriorating air filter element
- Crankcase ventilation system for correct operation-Refer to CRANKCASE VENTILATION SYSTEM INSPECTION/DIAGNOSIS .
- Water intrusion
- Vacuum leak and other un-metered air downstream of the mass air flow (MAF) sensor
- Intake manifold leak
Inspect the exhaust system for the following:
- Water intrusion
- Exhaust leak
- Damaged, restricted, modified or enhanced exhaust system-Refer to SYMPTOMS - ENGINE EXHAUST .
Inspect the engine mechanical for items that could alter the air flow into the combustion chamber. Refer to SYMPTOMS - ENGINE MECHANICAL .