Help required with fault

Hi guys.

Ive be had a fault on going for a while now. I've been led to believe it was the PCV valve. I've been getting the revs flutter after acceleration and going into neutral (see the video). I tested the PCV by removing the oil cap whilst idling and up to temp, you could clearly hear sucking and the car starting to miss.

Ive vey just replaced the PCV for the new revision R version and changed the gasket. The car is exactly the same as before. My engine code is BHZ if that helps.

Here re is a video of the rev needle showing how its hunting after accelerating:
Audi S3 8P fault? - YouTube

all help is appreciated.

My two options left are the check valve pipe work at the back of block or the vac pipes.

Ill do the easier option first of checking vac pipes. Can anyone tell me the rough locations of them all?

I've ordered the check valve pipe and changing that in the morning.

Does nobody have any suggestions?