I used seafoam and it makes a ton of smoke. No idea if it cleans anything. When I took the intake and head off they were still completely covered in soot. I used a wire brush on a power drill to remove it.
What I noticed when I took everything apart is the cylinders are oval, taper, and are on the large side of the factory spec. What that means is that there is lots of piston/ring blow-by, causing increased crankcase pressure. This blows the oil up through the PCV path into the valve area, where more oil is picked up in the blow by gas, and heads right into the intake. The catch can helps, but the engine could also be sucking in blowby gas and oil on the intake stroke when there's a large vacuum in that cylinder, but high pressure from another cylinder on the power stroke.
I'm ready for my 3rd rebuild but this time I'm going to get the cylinders cut to the smallest size that is a true cylinder (no taper, no oval). I just don't know what size piston to buy.
At this point, the car has no value, so I can do WHATEVER I want to it. I'm thinking about standalone ECU and maybe a turbo (I have a focus ST now and it's cool but i still love NA high revs). 100% custom exhaust, probably a full MSP suspension swap (still have the original suspension from 2003 after northern winter salt and 120k miles.