PCV leak

Any model info on that part? For future reference....

Now doe some heavy cruise driving on the engine (not WOT) some and see if the oil stays under control or if you get a lot of oil blown out. This is a check just in case the new-old PCV is fixing your idle by simple being a smaller flow item. If it too low a flow, it won't pull enough air at heavy cruise to evacuate the oil fumes adequately.