I changed out my old PCV valve, when I took out the old one I shook it and could not hear it rattle. Probably clogged with oil and other crap from the years.

So I replaced it with a MKIV Supra Turbo PCV valve
(these are more efficient than the Honda ones and are popular with people running small boost set-ups and no catch can)

It was an easy replacement and the new valve fit perfectly.
However... I've noticed my idle will be anywhere from 1200-1600 RPM.

WTF???

 

could most definately be the cause of the high idle. Each pcv valve is engineered for their application. They are calculated vacuum leaks in a way. Go get the pcv that is made for the engine. basically your creating a larger vacuum leak than originally designed.