Its the IMRC control box. There is a cable coming out of it that connects to the inlet manifold under the throttle body. What happens is that there is a plastic lever on the inlet that the cable attaches to. Part of the lever breaks off causing the cable to retract too far, thus stripping the gears inside that box. Have a look under the throttle body, you will see a cable flapping in the breeze that should be connected.

Ford have released an uprated plastic lever that is stronger than previous versions as it is a known fault.

You will need a new IMRC box and what is called a DSI clip!

Rich