The ECM is not even in the mix for spark while cranking, so you can rule out the ECM being the issue there.

The ignition will be base timing triggered directly from the ICM and crank sensor/dizzy reluctor. Once the engine goes above 400 RPM, THEN the ECM will take over spark timing.

You don't even need the ECM plugged into the harness and you will have spark in a properly running system.

If you have inconsistent spark you will have inconsistent fuel delivery.

Figure out your spark issue, then the fuel will probably follow in line.