Do These have a proper throttle cable or is it electrically operated?
Could be a sticky potentiometer? I don’t know how the Ford works, however generally speaking the Engine Control Unit/Engine Management System needs one attached to the butterfly spindle for the throttle opening. IIRC, some systems use inlet air speed sensors, but it’s a Ford so I would guess that the electro-mechanical device is used?
From reading the above posts so far, consensus of similar problems would err towards a throttle body issue that tends to be resolved with a clean.
Not wanting to p**s on anyone’s fireworks, throttle bodies are probably the simplest part on the modern car. If they are dirty, then the air filter is missing. Have you checked? What other dirt can get into a throttle body?
It’s a simple butterfly valve with a return spring. I used to ‘make’ them with a hacksaw from old Dellorto and Weber DCOE carbs.
I just wonder if the cleaning is more to do with the potentiometer?