Renix 4.0: Oil blowout from valve cover/airbox!

I have a '90 4.0 with about 180k on it. It runs well other than some lifter noise when the engine is cold. It had a number of oil leaks which I've been chasing down. I took care of the main ones (rear main seal, valve cover gasket) and degreased the engine to track down the remaining leaks.

What I found is that oil is being blown out of the oil filler cap, being blown into the airbox, and also has oil coming out of the big hose at the front of the valve cover. The oil cap is a simple unthreaded cap, and doesn't seal tightly.
The top end of the engine seems to be under a lot of pressure if it is blowing out so much oil. What could be causing this? Would a clogged CCV harness cause this kind of issue? I've read that the CCV orifice is really small, so I don't think it would result in such a big mess....

It doesn't bother me much (I'm down a little over a quart every 3k miles), but the complex is threatening to tow it due to the leak, so I'd appreciate any thoughts you guys might have.

Thanks!

Read this article for starters.....your problem is most likely a clogged CCV system which is extremely common for a '90.

http://jeep.off-road.com/jeep/article/articleDetail.jsp?id=257985

Yep, bet on the CCV system.

Also, there is a mod that Cruiser54 posted in this thread: http://naxja.org/forum/showthread.php?t=1026666

So, when you service the CCV and do the mod your problem should be greatly reduced if not eliminated.