Chattering sound on startup and accelerating

My Dakota's begun making a chattering sound on startup and when accelerating. After a brief check, I noticed the part circled in red has two bolts that I can see are broken off, as the whole silver colored piece can be wiggled freely on that end. It's the same area I tracked the sound to, but being fairly inexperienced I'm not even sure what part I'm looking at. If anyone could identify it I would be very appreciative.