In pipe who connect automatic tranny and intake manifold (signal of pressure in manifold) come oil from tranny and make plugs greasy.I discover that when i disconnect that line and drive some time.To be sure i install clear rubber pipe.Some oil come in pipe thru vacuum valve(?).My opinion is some membrane in valve is broken.What to do,try to open valve body or search for new one.
I have some pictures,but my phone is take day off .