Its starting to look like an internal ECU fault, but before we go down that route, the ECU appears to be happy with cylinder one?

So by connecting injector one wiring harness to the other three Injectors one at a time we can remove the injectors from the inquiry.

After that check the wiring at the ECU for short circuit, open circuit,and cross continuity.

After that (and checking all the ECU's power and ground via load testing) The ECU is looking pretty Goosed.

Mark