Idle up then down?

Assuming a 4 bbl and moderate duration cam:
1. The secondary throttle stop may be open too far
2. The PCV may not be suited for the cam; we cured your exact same problem past week by changing PCV. The original Mopar item was open too much at the 11-12 inch idle from the moderate cam and letting in a lot of excess air. Here is the solution thread for a different PCV; it settled it all down very nicely.

http://www.forabodiesonly.com/mopar/showthread.php?t=335105