So you just have an oil line going to the PCV block off plate? and the valve cover going to a sealed can? That's not going to do anything. Not sure I understand what you mean by oil line. Usually you do the PCV delete if you have a turbo. Ideally what you will want is a air oil separator and tie the "outlet" to the intake to have a vacuum. it sounds like you have essentially completely sealed any venting of pressure and its finding its way out through the seals.
Pull all that off and put a breather on the Valve cover and put either the stock PCV on the motor or install an air-oil separator and install the "venting" of that to the intake to remove pressure.
2001 ZX3 2.0L Zetec-
Hatch Nation #42
Going through Rebuild See "The TICK Build Thread" for details (http://www.focusfanatics.com/forum/showthread.php?t=289168&referrerid=62897)