Trivial to check. Just read the FAQ.

1. The flame trap insert must be clean. If it's not, get another one. $1 at NAPA.

2. The breather box must not be clogged. You can use carb or FI cleaner or other degunker to clean the inside with the box out. Just flush it with the cleaner, then with some fresh oil to get rid of remnants of the cleaner so as not to pollute the oil in your engine. Better yet, do an oil change a month or so later.

3. The "Tee" or "Y" nipple where the flame trap insert sits must have unrestricted flow in the small tube that attaches to a small diameter hose going to the manifold. This tube quite often gets completely plugged and you have to drill it out clean. That's what I had to do.

4. The small diameter hose going from the T/Y nipple to the intake manifold/throttle body must have unrestricted flow. Try blowing it with compressed air - it should pose virtually no restriction. If the hose is old, it's brittle so just replace it - you can get vacuum hose say at NAPA for $.50 a foot or so.

5. The brass fitting where the hose plugs into the manifold/throttle body must be clean too. Use the the famous device (a.k.a. straightened paperclip) to clean the fitting if it's plugged.

In case your PCV system was plugged, it was probably spewing tons of oil into the intake. That necessitates at least cleaning the throttle body and the large intake hose where the oil will typically accumulate on the bottom. You may also wish to remove the injectors and clean them - they will have some oil sludge deposited close to the jets. If you're unlucky, the spray cones will be distorted, or the injectors will drip instead of spraying. Better to get it cleaned - replace the injector o-rings while doing so.

Cheers, Kuba