Just in case you didn't know what the sparking test is it involves a spray bottle and water!

Mist down all the ignition wires on that drier day that it runs. You can it run it at night or in a closed up dark garage!

In shops that are open only during the day you might see them throw a blanket over the front end.
If you have never seen, that there is a reason for it!

For them, if the wires look a wee bit dirty or dried out, it is called "change the wires." The customer will foot the bill! Hello?

It is just a standard given, among many mechcanics, that this 100 year old technology just has its limits! Even with space age materials and mankind's willingness to get by on the cheap and those who want to make a buck!
There are several makers of wires, making two or three qualities of wires. Then they are pie into a gazillion brand name boxes. Printing on the outside of the box is super cheap!
I will also suggest going with the recommendations from posters on the board that follow their own advice. It's time and mileage proven.
I spot my well known wires at the junkyard, since in most cases, the car gets tuned up before it gets junked as a last effort to save it!

Spark plug wires need to be far less than ten years old. Especially when, you live in a wet zone and the car stays outside, I would check out the wiring and the connector to the distributors hall sensor like you were thinking.

Try using some dielectric anti corrosion paste in there. Same for the injectors clips, inside the terminal towers of the coil and the distributor. A real thin film is all that's needed as an insurance policy to keep these problems at bay!

Good luck

Phil