What is thisFast Idle Device 308 QV

Is this the fast idle device? I removed both air rails and this is what the vacum line go to. Can I unplug this unit with no ill effects as long as my vacum lines are plugged? Anyone else done this?

I don't know what year your 308 is but that isn't the cold high idle device. Try plugging it and see how the car acts. The little box looks like an electrovalve for the emissions. Since that is gone I don't think you need that.

Agree that that is an emissions electrovalve by the looks of it.
The aux air valve is a big ugly black thing with bigger hoses connecing the plenum and the airhorn downstream of the mass air sensor plate, typically.

On the 328 the AAV is unfinished aluminum and mounted under the coolant tank.
Mark

This is an electro-valve for the air injection system. The tube you have missing (on the white Tee connector) runs to a fitting located just under the throttle body. The metal fitting on the back side remains open to the atmosphere. Although it is not directly related to your idle circuit, if you dont have this squared away correctly, it will cause vacuum leakes, thus messing up your idle.

Thanks everyone. I disconnected this entire unit and plugged the lines running to the throttle body. I removed all of the air rails running to the heads so I did not need this anymore.