I replaced my PCV on my N12 engine several months ago with one from Ebay, the Chinese version which comes with the clipped cap, diaphragm and new spring. At the same time I also replaced both Vanos solenoids, lambda senor and other new parts. Since then rough idle and stutter in 3rd gear until engine warm.
Taken me until now to sort the rough idle out. Ended up taking the PCV out and compared the new and old springs, the original is much thinner and less resistant than the replacement, keeps the valve/diaphragm open much longer. Put the old spring in and went for a spin this morning - no rough idle and no hesitation.
There were no codes (not expected) and no obvious excess oil consumption. Am hoping a couple of thousand miles has not damaged my cat running it polluted.
Anyway, hope this helps someone else who may have fitted the replacement PCV from Ebay.

 

I got one of those too. Same result, idles smoother. Also seems to have reduced oil consumption.

 

To what spring are you referring? I am familiar with the PCV hose from the valve cover to the intake manifold and the red rubber diaphragm in the valve cover. Also, which sensor is the lamda sensor and why did you choose to replace it?