I remember when working in the tropics back in the seventies.
The job required series II Land Rover 6 cylinder versions. These cars had a lousy location for the coil - too close to the exhaust manifolds and under a leak spot off the hood. You needed to carry a spare coil around for rainy days or for going on long trips. Mountainous areas required to carry 2 spare coils and when they all 3 heated up they required an ice water soaked rag around them to keep them going.
When they were too hot - no go.

The moral of this story is that electronic components function differently under operating conditions than they do on the bench. That is why I inquired whether or not the components were actually changed out and run on the car rather than just a static test.