What sensor is this? 3sgte in a st, Noobish i know, but not sure how it ended like this Options

[eggman40]

I recently got a new air fuel gauge and ive been monitoring the car for a week now. At first it was running fine, just a little bit rich but not out of the ordinary. As of monday though, the car has been running REALLY rich and the weird thing is my BOV doesnt sound off as loud as it did last week! Im still boosting correctly but the sound is not as piecing as it was. even at wot you could bearly hear it now.



Any way i wen into the engine bay, looking for a loose vac line and i found this:









Im not sure why its loose or if it was attatched to something to begin with. the hose you see was just dangling. I dont remember this when i was doing the swap Anyway, what does it do? is it crucial? or is my problem elsewhere? any help is appriciated. Thanks!

[lagos]

yeah, a leak would change your idle.
just look around that area of where on the motor it came off from. you should hear it hissing, and your vac readings should be low.