I has the same setup. Two options: a) you made and put all the PCV plumbing (as I make), or b) open and clear the solid oil cap (the cap have 3 screws, open it, clear it and replace the internal metalic mesh - I use some stainless steel mesh hijacked from the cook cleaner kit of my wife).

Two year ago, after I buy my car, I check the cap, and that was a internal messy mud of oil and dirt, blocking the flow of air into the engine (at some speed the car made a venturi effect on the oil dump tube, flowing air into the engine).

Btw,I move to the PCV setup as a prevoiusly step to convert my car to use LPG.

Also, of course, the use of the PCV plumbing help the enviroment...(put your favorite tree hugger´s advice here) :-)

Happy Volving

Joaquin
Rojo 121 Amazon
Lima Peru
http://www.volvoadventures.com/121spec.html