[ImperialCrown]

Actually the airflow should be from the breather tube into the crankcase then sucked through the PCV valve and burned in the engine.
Excessive blow-by maybe from a wrong or failing PCV valve, wrong or thin engine oil or failing poorly sealing piston rings.

 

[Bob Lincoln]

On my 93 TBI, I thought I had a breather hose problem or blowby problem, because oil was puddling up underneath it on the transmission case; and it wasn't coming from the valve cover gasket.

Turns out it was the head gasket leaking at the driver's rear corner. It used a quart every 1,000 miles, and it would puddle within a couple of days. After the head gasket blew and I fixed it, no more oil puddling, and consumption is over 2,200 miles a quart.

 

[ImperialCrown]

There is a high pressure oil galley passing through the head gasket to lube the cam in that corner. Leaks were very common.

 

[Bob Lincoln]

Ah. That might explain why the cam makes more noise than my last 2.5L; and I bought the last one new, this one I'm at least the 3rd owner, so I don't know how it's been treated.