Vacuum Switching Valve??

So it's been ages since I last posted on this site. I'm still fixing/modding myself because I've been able to find all of my answers by (believe it or not) using the search feature! and Google.

Anyway, for awhile now I've noticed an inconsistent vacuum noise (as if its struggling to bring in air) on cold starts. It goes away after about 30 seconds. I finally thought about pinpointing it and I think I found it. When I touch this thing on the left side (seems like there is a hole or 2 for air), the noise is altered, so I assume it's coming from it

Edit: I mislabeled the strut bar as a sway bar :tomato:




So some searches on the part number tells me it's a Vacuum Switching Valve Solenoid of some sorts. Further, I was able to find it in an exploded view in the intake manifold parts page (B-47) on http://www.oemacuraparts.com/ but with no part number, and I can't find it anywhere else. What does the B-47 indicate?




I'm not even sure if it's causing a problem, I just don't like the noise. A few questions:

1. Does everybody else have this noise or is this abnormal?
2. Is this actually a "Vacuum Switching Valve Solenoid"?
3. What does it do?
4. Is this Denso part OEM or has it been replaced before?
5. What is the part number to replace it?

Thanks!