High pitched noise coming from WUR

[SoCal911SC]

So I was having some issus with a rough idle, among some other things, but I thought I'd take a look in the filter screen of the WUR to see if I had any blockage. Seemed innocent enough.

Ultimately there was no blockage, so I reinstalled the WUR and now all of a sudden there's a high-pitched hissing noise coming from it, and now the car just dies when the RPM's settle after revving. It didn't do this before when cold.

I'm cunfused how simply taking off the WUR (NOT EVEN OPENING IT UP!) and reinstalling it can cause this issue. Any thoughts? Thanks.

[ossiblue]

I suspect you have an air leak somewhere close to the wur that is coincidental to the r/r of wur itself. Hissing strikes me as a vacuum leak. Could you have dislodged any hoses or lines during the wur service? Do you have a vacuum connection to the wur itself? The original rough idle could be due to a vacuum leak, maybe from a cracked hose, and your moving of the wur simply caused the crack to increase leading to enough of a leak to prevent idling at all. It's worth a check, IMO, to listen closely for the hissing and determine exactly from where it's emanating.