My son's 90 4.0 has an oil leak that I'm trying to diagnose. The emissions junk has been removed from the rig, ie the airbox, etc. The forward hole in the valve cover I believe originally contained a tube going to the factory airbox/intake, but since the removal of both of those items, the po stuffed a chrome "Mr. Gasket" oil breather in that hole, which now appears to be puking oil out while driving.

SO, the question- is this to be expected with a jury-rigged setup such as this? OR, do you think there's some engine problem causing excess pressure under the valve cover and expelling oil out the breather?

Thanks!
Tony