Originally Posted by IndySilverAnny

Bringing back this thread from the dead.
My truck is doing this exact same thing. Ran codes and got the codes for running lean on both banks. It was making the noise intermittently for a while, then recently started surging at idle, with the noise coinciding with the surges.
Checked all hoses. Replaced one elbow on the back of the intake that was dissentigrated.
Replaced PCV valve, IAC (twice. 1st one from O'Reilly's, 2nd from Ford), and even upper intake and EGR gaskets. Replaced fuel filter also recently.
I do have the stock intake tube with the baffle cut out and the intake elbow mod with a stock paper filter. That was done long ago, and the noise just started recently.
If I pull the hose off the PCV valve, the noise stops, but the truck starts to die. If I put my thumb over the end of the hose, it starts to make the sound...

I'm thinking I got a defective PCV valve, as I'm able to blow thru it in both directions.

I'm amazed that as popular as these trucks are, nobody stocks the PCV valve! O'Reillys will have another one later this afternoon.