PCV Valve is part of Postive Crank Ventilation (PCV) System. The system comprises of PCV valve, Suction pipe and filtered air pipe. PCV Valve sucks oil fumes at designed RPM (oil fumes are produced due to eng temp & mostly minor blow back by pistons' rings (normal). Filtered air pipe sends clean air in the oil sump to fill air gap created due to oil fumes suction. If PCV valves gets stuck at close position, then there is positve pressure thru filtered pipe and when accelerator is depressed suddenly, it creates back pressure, which carries oil n its vapours n thus throttlebody n intake get dirty. Moreover, at higher rpm when filtered air pipe keeps supplying positive pressure in crank case, which cannot be escaped thru stuck closed PCV valve, thus it results in oil seeping out from head cover Jane. If it sticks at open then, you find RPM fluctuations and driveability issues. If filtered air pipe gets clogged n stop pumping air in oil system to fill gap due to suction, so the vacuum will start buildup in Crank case/oil system, which will affect engine performance. This complete system was introduced in vehicles to reduce hydrocarbons emissions, thereby enhancing fuel economy. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-PlyKU6tbQXs.htmlsi=cekAqqRFd7Y45a-t
