Went to replace spark plugs and found oil in number 4 plug well .So usually it’s the valve cover leaking. I bought new covers and gaskets, my left side was way bad , the seal was cracked and exposed to the inside metal.On that side no oil leaked. Right side (passenger) was brand new. But whoever did it , used to much gasket maker and it caused my valve cover to warp and therefore leak. My intake manifold was filthy, upper and lower plenum needed cleaned as well. All my breather hoses were rock hard , like glass, so I replaced three of them from Z1, silicone. My fuel pressure damper was badly damaged too. So new one there. I went to start her and she sounded like she wasn’t getting enough oxygen. Are the PCV valve on the new valve cover working valve? Or just to plug the hole? I changed it and she sounds good again.
I’m a DIY not a professional, do I need advice on this. I’m good mechanically, do bare with me.

Top end 2004 350 Z

My engine bay

Finished

Complete and detailed

Ready for work

Side shot of engine bay

Another view

Tear down

Valve cover and IVT solenoid

Intake

Tear down

Front shot

Dirty plenum

Filthy

Fuel pressure damper and evaporated canister

Intake manifold and fuel rails

A double

The engine bay

Wire harness

Double again