Are you having a problem with high idle or rough idle? I assume both can be present at the same time but often it’s one or the other. Unfortunately I’ve had experience with both.

You seem to be referring to a high idle so I’ll address that.

Yes, the idle adjustment screw does contact the sensor plate lever but it does not have any contact with the fuel distributor; the FD is effected by the position of the lever which indicates the amount of air entering the engine. The adjustment screw is more for ‘fine tuning’ than addressing a major high idle problem - which would explain why your adjustments of the screw have not solved the high idle.

I suspect you have an air leak. The idle control valve may have failed and is allowing excessive air into the system resulting in the high idle.

The best scenario would be you have access to a good functional ICV from a 116/117 to test in your engine. Failing that a 24-hour soak of the valve in brake cleaner may free the mechanism. My ICV eventually had to be replaced which solved my high idle.