2002 Buick Lesabre Ignition Module Failure

About 2 years ago, I had the engine replaced. Shortly after that, I had a problem where the car would turn over, but not start. Diagnosis by the engine installer, was a bad ignition module. He had reused the original module when the engine was replaced. The module was replaced. The coils were reused.

Several months later, same problem (went to my regular mechanic); diagnosis was bad ignition module. Replaced the module - "replacement must have been faulty", reused the coils.

Several months later, same problem. Regular mechanic noted one of the coils was much hotter than the others and replaced all three coils as well as the module.

Several months later, same problem. Regular mechanic replaced all three coils as well as the module.

Yesterday, it happened again. Clearly we are not resolving the root cause of these failures. The mechanic uses a conductive thermal grease to ensure a good ground between the module and the block. Could there be other ground connections left off, or in poor condition following the engine replacement that need to be checked?

Can you think of any other causes for these failures?

Thank you for any help you might offer.

Regards,

Bob