[wiswind]

The fuel injectors do make a clicking sound, but nothing near what I heard in your video.
The clicking sound is because the injector has a plunger inside.....and a electrical coil in the injector body.
When current flows through the coil inside the injector, a magnetic field is created which pulls the plunger up.....opening the valve that lets fuel flow through.
Then when the current stops flowing, a spring inside the injector pushes the plunger back down, stopping the fuel flow.
The current flow is only for a super short time......
The plunger moving up and down against the limits creates a small ticking sound.

The current through the coil is driven by the PCM (computer).
When the ignition is ON, there is always 5 volts to 1 of the terminals on the fuel injector electrical connection.
A transistor inside the PCM turns on to create a momentary path to ground to the other terminal on the fuel injector when the PCM wants to squirt fuel into the cylinder.

Waisted Spark.
This is not causing a problem.......seems a strange way to do things but it is very common in modern engines.
For the 6 cylinder engine, there are 3 coils.
Each coil has a spark plug on each end........so each coil fires 2 cylinders.
Each coil has a primary winding which is low voltage.
The primary windings are driven by the PCM.
When current flows through the primary of one of the coils.....the secondary generates a high voltage.
Now....this is where it gets interesting.
The voltage generated in the secondary winding is measured from 1 terminal to the other.......and 1 end is a very high POSITIVE voltage, the other is a very high NEGATIVE voltage.......if you were to measure each end with 1 meter lead on the coil lead and the other meter lead on GROUND.
NOTE, do NOT try to measure this......I'm only explaining how waisted spark systems work.

So, when you energize the primary (input) winding on one of the coils, the secondary (output) winding generates a high voltage at both of its terminals....which is where the spark plug wires connect.
1 spark plug fires with a POSITIVE voltage (relative to ground)
The other spark plug fires with a NEGATIVE voltage (relative to ground).

Why is this important?
The spark plug fires because of the high voltage between the center electrode and the ground tab.
Since 1 side of the motor has POSITIVE voltage causing the spark and the other side of the motor has NEGATIVE voltage causing the spark......the wear on the spark plug will be different on each side of the motor.
1 side of the motor will wear the center electrode faster.
The other side of the motor will wear the ground tab faster.
THIS is why you should use double platinum spark plugs in this vehicle.
Double Platinum means that the center electrode AND the ground tab have the platinum enhancement. (not multiple ground tabs like the Bosch +2 and +4 plugs do).

As far as the air/fuel mixture inside the cylinder, a spark is a spark.....it does not matter what voltage caused it.
What does become critical is that the spark plugs wear somewhat evenly between sides of the engine.
A small variation really won't make a big difference, but a big variation (spark gap getting a LOT biger on 1 side as compared to the other) then problems can develop.

On the older windstars, like my '96.
The FACTORY spark plugs on 1 side of the engine had the platinum enhancment on only the ground tab (you can see it on new plugs)......and the other side of the engine had the platinum enhancement on only the center electrode.
There was a EE on 1 side and some other letters on the other side (EF?).
HOWEVER, replacement plugs that you get at the dealer or aftermarket have the platinum enhancement on both.....the factory plugs were used ONLY at the factory.....I would guess a cost savings.