Injector not firing.

Hi everyone. New here and hope that this issue hasn't been beat to death but hoping to find some good advice.

I have an 03 outback with the 5.7 and when I put it in the lake this weekend it had no power. Changed out spark plugs and new fuel filter but no help. So while checking out the TBI I noticed one injector wasn't working. I can switch the connectors and it will work but the other one stopped working so not a plugged injector. I kept playing with connection until it started working and boat ran fine for an hr then no power and injector stopped working again. Removed harness and checked resistance and harness seems fine. Anyone else had an issue with this? Any advice would be greatly appreciated. Local service shop is backed up by 3 weeks