UPDATE: It has been confirmed, the ignition coil driver was bad in the ECM. It has been repaired and it is coming back to me. I will have my van in working order again this weekend. My ECM is MECM-C703-A1.
By the way, there is a very good article in http://www.easyautodiagnostics.com with the title “Power Transistor Test and Ignition Coil Test 3.3L Nissan”. I found it later and it is very good. My final diagnostic came after going through all computer inputs and outputs with an oscilloscope comparing wave forms per service manual.