87 Brat, EA81 with SPFI conversion. There is a fair amount of oil always sitting on my IAC. My guess is that it is coming from the intake, and leaking down. But the question here would be why is this much in the intake? Can the PCV valve somehow cause this? Or am I looking at a more serious problem?

Yes, PCV has something to do with the Problem.

 

Your EA81 has the EA82 Fuel Injection Intake Manifold, isn't it?

 

I Kindly Suggest you to Post here Pictures of your actual PCV Routing, in order to Help you Better.

 

Kind Regards.

The oil leaking onto the IAC:

 

 

PCV routing:

 

Until recently I was running the same setup. Mine was a freshly rebuilt EA81 with SPFI. I tried both the original SPFI routing of the PCV and the dealer modified version with the new blue "tee". I always had oil in the intake around the IAC and in rubber intake bellows. It bothered me, however I spent so much time chasing valve train issues and low end drivability issues I never did get around to solving it. Good Luck