Again Oil in J-Tube after replacing AOS

[JP986]

A few weeks ago I replaced my Oil separator with the new updated version on my 2.5L Boxster with 90k on it (proud daily driver). I also replaced the J-Tube (thanks to Mike Focke!), but afterwards the car was still running bad - black smoke (especially at higher rpm's) and when I stop to accalerate (driving with constant speed) the engine is stuttering. At my service station they replaced the sort of EGR valve (cut-off valve), cause they thought it is a secondary air problem - it didn't changed a thing.
Yesterday I wanted to clean the throttle body and I noticed the new J-Tube from the AOS is full with oil again!!! Does anyone has an idea what's wrong with my car?

I still have engine failure codes from all O2 sensors and a lot of missfires on both banks. I think my entire system runs too lean and that's why the engine get's sometimes too much fuel injected (black smoke). I checked the car for secondary air leakages and already replaced the MAF....