The throttle potentiometer will report the throttle position to the ECU. When this is not done correctly, the ECU will assume a certain throttle position, where the real throttle position is different.

This can result in a number of symptoms, like irratic idling, bad performance etc

This is a brand new throttle potentiometer, which will fit all 48mm and 52mm throttle bodies.

Genuine X-Part (Rover) part.