Positive crankcase ventilation valve (PCV)
While the engine is running at x x rpm, disconnect the PCV valve from the valve cover. If the valve is working properly, a hissing sound should be heard when air passes through it, and a strong vacuum should be felt when plugging the valve inlet with a finger.
PCV Ventilation Hose
1. Check for leaks from hoses and couplings.
2. Disconnect all hoses and clean with compressed air. If a blockage in any hose cannot be cleared, replace it.