Back of intake manifold: What is it? (archive)

Got a 1994 740 M60 V8. Saw this "thing" bolted to the back of the intake manifold with 7 #30 torx bolts (suspect some variation of PCV - got to remove coolant resivoir to get to it).

The reason for all of this is a "sometimes" crappy idle.

Took that "thing" off & cleaned the heck out of it. It was dirty as sin. Also saw a small pool of oil in the intake manifold where the thing came from. That area also dirty as sin. Cleaned all, replaced all (no new - replaced what was there, cleaned).

At the very bottom of this "plate thing" is an air port. It appears to vent (out) rather than vacuume (in).

Covered it with duct tape & engine blew oil from the oil cap & dip stick. Burnt like heck. Folks at the store thought I was on fire!

Removed tape on this unknown port & engine seems to run OK, at least in the garage under no load but various RPM's from 1K to 5K. Not much smoke (maybe left over from before) and idles OK.

Question: What is that thing bolted on the back of the M60 intake manifold and what does it do & how can it affect idle quality?

I'm lost! What the heck is this thing/system???

Thanks in advance!

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