I have changed the ignition leads before 16.000 km. The new ignition coil was way more expensive, but the mechanic first told me to start with the ignition coil and the new one solved the problem. I was just confused when the mechanic told me that one of the cables was hard for attaching to the ignition coil, but he somehow managed to do that and after that he told me that the spark plug wires were good. According to what I described in this comment and in the entire post, is there a possibility that the new ignition coil did not fix the issue, but the reattaching of the spark plug wire? Could it have been loose? Could the old ignition coil be still good, so I don’t need to dispose it, but keep it instead?
If you think the old coil is good, examine it around the area the ignition lead fits and if you can see no damage refit to car and try it.
However I would advise a careful inspection in the area I mentioned for tracking and spark damage, it can look like a crack but is caused by the spark taking the easy route especially if damp or dirty rather than firing the spark plug.
The metal part of the ignition lead needs to sit as deep as possible inside the neck of the coil so no chance of as poor connection and must be secure.
On a slightly different point, one of my sisters had a Honda, bought new from the dealers and always serviced by them, she mentioned that after reporting an intermittent misfire she had new expensive genuine coils fitted on several occasions.
I advised her to have new spark plugs fitted even though the Dealer said they were not needed at that mileage, she insisted on my advice and it cured the problem.
The reason being as the plugs wear the gap gets wider and the plugs need a higher voltage from the coil to spark the plugs.
Another point that makes matters worse is modern regulations mean ignition systems have greater radio suppression resisters fitted , so you have suppressed HT leads made of carbon string which breaks easily internally so not visible, resister spark plugs and in some cases resisters in the rotor arm where used.
All these make the voltage higher, so like water more likely to take the easy path/route and short out.
As an apprentice in the 1960s cars ran happily using 6000 volts to fire the spark plugs where as nowadays it is more likely to be between 20,000 and 100,000 volts in some cases.