Circuit/System Testing

Verify that none of the conditions listed below exists with the air intake system:
- Damage, restriction or modification
- Dirty or deteriorating air filter element
- Crankcase ventilation system for correct operation.
- Water intrusion
- Vacuum leak and other unmetered air downstream of the mass air flow (MAF) sensor
- Intake manifold leak
- If a condition is found, repair as necessary.
Verify that none of the conditions listed below exists with the exhaust system:
- Water intrusion
- Exhaust leak
- Damaged, restricted or modified exhaust system - Refer to Symptoms - Engine Exhaust .
- If a condition is found, repair as necessary.
If all of the above conditions test normal, inspect for an engine mechanical condition that could alter the air flow into the combustion chamber. Refer to Symptoms - Engine Mechanical .