Loosing cylinder 456

[Weekend warrior]

Sounds like all your missing is an engine harness or an injector harness, sounds like you have 1 of the rear bank cylinders shorting out and since the ecm is load limiting and cannot determine which of the 3 cylinders is causing the short so it shuts down the whole bank. Ecm has 2 injector drivers, a front bank and a rear. I’ve seemed it a hundred times, either the coil on the injector, injector harness got rubbed somehow, or the engine harness got chaffed somewhere, especially if you have eliminated all the other components. Hope this helps