1996 T444E injector short

This can take awhile. I have a 1996 international T444E 7.3 diesel that came into the shop that had no power. Ran code reader and had codes that lead to the ecu. Got that replaced and did testing, next thing replaced was the IDM. Came up with short on number 7 injector. Traced out the wiring and replaced engine harness to injectors, valve cover gasket and undercover injector harness. Also replaced number 7 injector. The truck will idle fine but a soon as you throttle it up it shorts out on number 7 injector and throws two codes, 544 and 457. This has been a thorn in my side for the last week. Someone out there must have an answer I hope. My hair is getting super thin from pulling it out!!