Frontier XE King Cab 2WD V6-3.3L (VG33E) (2001)
Positive Crankcase Ventilation Valve: Testing and Inspection
With engine running at idle, remove PCV valve ventilation hose from PCV valve; if the valve is working properly, a hissing noise will be heard as air
passes through it and a strong vacuum should be felt immediately when a finger is placed over valve inlet.