I'm wondering if this could be the PCV, I replaced the pipe and rubber to the turbo but TBH the old one one looked OK. During a test drive shortly afterwards the car started running rough on idle with the the CEL flickering on and off, which cleared itself after giving it a boot down the road, put my cheapy diagnostic tool on after and it said misfire on cyl 4. I had the PCV off and it all looks ok underneath with the orange valve moving ok, but the symptons do relate to a you tube video from Deutshe auto parts?
I see Febi Bilstein do a replacement PCV which is alot cheaper than the dealer part, can anyone vouch for this part, Febi are usually pretty good quality in my experience
Many thanks