Thanks for sharing both your foible and perhaps more importantly it`s fix, which seems likely to help others similarly affected in future...
I find myself questioning as to why it seems fuel pumps became fitted within the tanks, as opposed to externally.
At a guess given early fuel injected sports cars such as the TR5/6 had issues with overheating pumps causing a degree of fuel issues, perhaps caused others to think of submerging the pumps in the fuel for cooling purposes...?
70`s fuel injected Porsche 911`s seemed to have no notable issue with electrical pumps mounted outside the fuel tank, though as best I can remember they were fitted approximately level with the pickup point of the fuel tank.. at the front of the car and likely exposed to quite some degree of airflow..
Since the arrival of EFI and digital control, the diagnosis of issues has become ever more complex even for professionals, unless the fault without any code generated, or a random code, was previously found, repaired and the cause recorded/remembered..?