Vacuum Restrictor
WARNING: This page is about a different car, the 1995 Ford RV Cutaway, 1995 Ford Econoline, 1995 Ford Cutaway, and 1995 Ford Club Wagon. However, it is still accessible from the selected car via links, so may be relevant.
This orifice-type flow restrictor is used as an emission calibration to control flow rate and/or actuation timing of components and systems.