How much oil in your intake manifold is normal?

I've got an 07 LR3 HSE 4.4L with 153k miles that I've owned for 6 months. it seemingly runs great, good gas mileage, occasional P0420 and P0430 cat efficiency codes which may or may not be related.

My intake manifold has a thorough light coating of oil with a handful of darker residue-y spots. The throttle body plate was a bit gunky on the backside of it which made me think to check the PCV valve since its breather goes to the throttle body housing on the back side of the throttle plate.

PCV is not clogged, and I sprayed MAF cleaner inside it and shook it real good just in case something is seized in there. same. I also checked and cleaned the 2 breather lines (1 connecting PCV to throttle body housing, and the other that connects the other valve cover to the air intake duct). nothing was overtly clogged. I checked the next day, and the light coat of oil was back.
I've got a new PCV valve on the way for good measure as I can't find a way to test LR3 PCVs since they're an odd design.


So at this point, I'm thinking I may have higher than normal crank case pressure causing this. because it's running so well, I'm assuming I don't have any glaring blow-by issues.

also, should I remove the upper intake and dump it out? I read it's not atypical to have a few ounces of oil sitting in there. if so, is that a fairly straightforward DIY task?

Could oil in the intake be causing my cat codes? this vehicle's prior owner did report that it had a severely clogged PCV last year which caused lots of oil spewing everywhere.

Sorry for no pics. i realized only afterwards that I should have photographed prior to cleaning.

 

....did the PO replace the PCV at that point?

 

PO did say he replaced it himself at that point.

 

From what I have read it pretty normal, but it could be residual from the PCV issue. Obviously if you remove it you will want new gaskets on hand. Also if you mess with the throttle body, I highly recommend using a new gasket.