This is computer controlled
Idle is computer controlled and can NOT be adjusted.
You can't. The idle speed is controlled by the Engine Control Module or ECM.
You probably can't. fuel injected cars have the idle set by the ecm.
There is no adjustment, the idle is controlled electronically. If you have idle problems you may have a vacuum leak somewhere.
The idle is control by the idle air control motor from outputs from the Engine Control Module.
In most 1990s and later vehicles you cannot adjust the idle. It is controlled by the ECM or computer. An idle that is not correct indicates something like a vaccuume leak or a sensor issue.
Ford stopped manufacturing the Falcon in 1970.
Idle speed is set by the PCM and is not adjustable. The screw you are fiddling with is just the stop screw to adjust the initial throttle plate position, it should not be used to attempt to adjust the idle.
The idle is controls ONLY by the PCM. Replace your ECTS along with cleaning the Idle Air Control valve located on the throttle body.
Why adjust idle... if this is a n/a you need to just leave it alone unless you have a consistent idle less than 900 or more that 1100 .... You will get no gain from this and if you don't have a consistent idle there is probably something else wrong.....
At the base of the carburetor are 2 screws. One adjusts the idle speed and the other adjusts the idle mixture. Screw the idle mixture in until the engine starts missing then screw it out 1 turn. Then, adjust the idle speed screw to about 850 RPM.