Oxygen Lambda errors

[Old Navman]

I think I read on here that you can buy just the pcv diaphragm aftermarket.
Once the diaphragm breaks it’ll start running rough quickly. You still need to diagnose it first though.
You also have that p0040 code. Has anyone mucked around with the exhaust or the o2 sensors? If they are around the wrong way it’ll add/remove fuel from the wrong cylinders.

Yes, I did see the post by Ian and the youtube video on how to get to the PCV but I think that was on a 2L engine not the V6?
Edit: the video was on V6 engine but only relevant to R32 Mk5.

No, nobody has touched the exhaust. I got the front end bushings done including the sub frame bottom engine mount bushes. But as I had to order the single use TTL sub frame bolts from VW (they had none in stock) I had left the splash shield off. It's been raining here heavily and I'm wondering if leaving the splash shield off could have somehow affected the sensor probes?