I sent the ECM to FL for repair. I am awaiting for their call to let me know what they found or to ask me additional questions to understand the issue.
I love this van too, this is the first time it fails on me like this at 237,000 miles. I was impressed with the compression test with this hi mileage at 180 psig, that is awesome. I can say it is a tribute to using AMSOIL 5W30 signature full synthetic which, by the way, I change only once a year as AMSOIL recommends. I also sent the oil to an independent lab for analysis and it really works.
The crankshaft sensor was good, I got a very nice sine wave in the oscilloscope. I also checked all other inputs and outputs at the ECM terminal block. The one signal that was not convincing was the firing signal to the distributor. That probed the whole thing, the problem was inconsistent spark.