I have a PCV valve on my car. The thing would flutter and make a rattleing noise sometimes. It was annoying and my A/F mixture never seemed to stabilze(want the mixture screws to be in the same position from one day to the next). I finally pushed a small socket into the line near th carb. The socket had a hole all the way through it, but it was smaller than the inside diameter of the line, about half the size actually. That eliminated the PCV flutter and seemed to help with smoothing the idle and stabilize the A/F mixture.

Those that have trouble with PCV valves either flowing too much air to get good idle, or rattling, usually have vacuum conditions that don't match the PCV valve. There are multiple flow rates built into the valves for idle, high vacuum off idle, etc. If you have a cam that is giving low vacuum, you could be into a higher flow area of the valve curve. You can get valves that work with different vacuum situations, but they can be hard to find, or you can mess with the spring yourself, which works pretty well.

If you Google PCV valve operation, you should be able to find quite a few sites that explain the operation of the valve very well.

I think you have the answer to my question, but I am pulling my hair out, so let's see.

I am getting a rattling in the pcv valve during idle - it idles rough only when the pcv rattles. She accelerates no prob, and the rest of the driving experience is great, but cold starts have lots of misses through the exhaust and the rough idle is killing me.

Idle vacuum is 22 inches steady, no vacuum leaks that I can find at all.

Well it seems that a little of all remedies helped me out, so I will share them.

It seems I was pulling too much vacuum for the little pcv valve that comes stock on just about all dodge motors it seems. So I took a page out of my past and got a pcv valve from a 1968 Pontiac Catalina with a 400 2bbl. That car had 10.5:1 compression and pulled 22 in. of vacuum when I owned it, so I gave it a try and it WORKED! Before I put that valve in I tried the socket restriction thing, I have not taken it out yet.