Specifications

condition may be present. The vehicle operator may experience an engine spark knock during acceleration
and/or an increase in the amount of engine oil consumed by the engine.
DIAGNOSIS:
Make sure Technical Service Bulletin (TSB) 18-48-98 has been performed.
NOTE: IT IS IMPORTANT THAT THE COIL AND SPARK PLUG WIRES ARE ROUTED EXACTLY
AS SPECIFIED IN TSB 18-48-98 TO ACHIEVE THE MOST BENEFIT.
Inspect the Positive Crankcase Ventilation (PCV) valve. Shake the PCV valve to verify that the pintle
inside of the PCV valve is free. Replace the PVC if the pintle is not free.
If the intake manifold plenum pan gasket is leaking, an additional vacuum source will be created inside of
the engine at the location of the pan gasket leakage. Engine combustion blow-by gases, oil vapor, and air
from the crankcase filter/breather may be drawn past the leaking pan gasket and into the intake manifold. In
most cases when this condition occurs, an engine at idle will create the highest vacuum and lowest amount
of engine blow-by.
1. Allow the engine to reach normal operating temperature.
2. Stop the engine.
3. Disconnect the breather hose from the air cleaner.
4. Attach a vacuum/pressure gauge to the end of the breather hose (Figure 1).
5. Disconnect the PCV valve hose from the intake manifold.
6. Seal off the intake manifold PCV valve hose port opening.
7. Seal off the open end of the PCV valve hose (Figure 2).