Engine Bucks

Engine idles fine. After acceleration it bucks badly and after stepping on the gas picks up but does it again almost immediately. There are two almost identical plastic electrical rectangles by the throttle cable. One has what appears to be a steel roller

There are two small electrical rectangles the throttle cable runs between. It appears to have a small roller that rides on the cable. I dont know what these parts are called. I suspect they have something to do with the acceleration and idle. The one closest to the firewall is broken and I suspect that is the problem but dont know what part name to even ask for. Thank you in advance for your time and expertise. Kris