Unquiet idle 3.7 AKJ, comparative values?

Hello together for now... again a new user here in the forum.. ;-)

Maybe I can find help here in the forum?

Have since October last year an A8 3.7L (AKJ) V8 Bj. 98
with 160 TKM on the clock.

So here's the thing.
- Slightly restless idle
- LL speed is external temperature dependent (if engine warm)
==References== 850 UPM / larger 10 C, approx. 600 UPM
- when opening the oil filler cap (or oil measuring rod) no change in engine speed or increased round motor run noticeably... no noticeable vacuum on the vacuum hoses. Brake cleaner test on the UD hoses unsuccessfully.
-Error memory over (VAG-COM) says only 01183 - Controlamp for catalyst (K72)
- All 3 slimes of crankcase ventilation already exchanged there porous. After that slight improvement.
- Throttle valve and 90 degrees arc resealed.

PS: How should the AKJ motor react in case of false air (oil cover/furling rod open) ?

I hope someone can help me...

Greetings Thorsten