Input please?!

[Danger_SSOAU]

Hey guys, I was wondering if anybody could help me out here...
Recently I have been cleaning out my Butterfly, IAC valve, etc. on my Gen2 and I noticed this sort of valve that is connected to the plenum...
The black knob on the end is adjustable, I turned it a little while the engine was running and it didn't appear to make any difference to how the engine ran.
Just wanting to know what it is and what it adjusts...

Here is a picture of the valve

[mcx]

idle-up for the a/c

[Doctor J]

the black "knob" is just a vacuum filter

[aych]

i've been having issues with my idle up for a/c. so i should just turn on ac, idle the car, and adjust it until it becomes smooth?

[mcx]

there is no adjustment...it either works or not..you could try cleaning the corrosion on its electrical plug.

[Danger_SSOAU]

Cheers guys