oil in intake manifold

I have a 4.3L V6 out of a 1996 S-10 that I'm putting in another vehicle. The engine was a dealership warranty change out with only 6,000 miles on it. From what information I can get, it was "losing oil", but after the change out was supposedly repaired. When I received the engine, the intake manifold bolts were lose and the gasket was broken. Went ahead and pulled the IM off and noticed oil in the bottom of the manifold. Spark plugs in cylinders 2 & 4 are somewhat fouled. I have read where a bad pcv valve can cause these symptoms. Anything else I should be checking or concerned about before reassembling and installation?

Yip, stuck open PCV valve can cause this.

Also make sure the fresh air intake pipe going to the passenger side valve cover is not plugged.