Car stalled out

[Ernest J.]

My son was driving his 1988 Pontiac 6000 the other night. While driving at around 30 mph, the car engine stumbled and then died. He tried multiple times to start it. It would turn over but not start. After sitting on the side of the road AAA finally arrived and towed him and the car home.
Just after the tow truck lowered the car to the ground, my son tried again to start the engine, it started no problem. All this in a matter of one hour.
We initially thought it could be an intemittant problem with the ECM, we replaced that with a Cardone ECM from Auto Zone. The car started, we thought we fixed it.
My son then changed the oil. When he went to start it, to take it off the ramps, it did the same thing, turn over but not start.
I hooked up my inline spark plug light indicator tool. I had my son try and start the engine, then I saw there was no spark.
This car has no distributor only what looks like a coil pac with 6 posts for each spark plug wire to plug in to, from there they go to each plug.
I had my son try and start the engine while I hit this coil pac with a handle of my hammer, just then I got spark and the engine started.
A couple of things, I'm having a problem identifying if this engine has an individual coil that sends spark to this block pac or does the block pac control the ignition?
The engine is the 2.8L, V6. Throttle body injection. No distributor.
I did check for any codes. Nothing indicating ignition.
Any help and ideas would be appreciated.
Thanks a million,