I have a little more information and want to see if anyone has additional insight.
The dealer is still reluctant to to look at the PCM as the culprit since the latest coil hasn't failed (yet). I also haven't driven the van much since the latest coil replacement, but I am sure that it will eventually fail.
During this latest coil replacement, the dealer said that they found the resistance on the battery negative cable to be a little high and claimed that this could be the cause. Maybe I am missing something here, but it would seem that a high resistance would reduce the voltage and power rather than increase it and cause the coil to burn up.
I have not been able to check the voltage at the coil primary leads, yet, but I did check the alternator voltage at the battery. It is no higher than 14.28 volts, even at very high rpm.
When I am able to check the coil primary voltage, what value should I expect to see if things are operating normally?
Thanks again for any help that you can give.