When the fuel rail is out and your checking for leaky injector(s), do the injector harness have to been connected to them? On my cousins 88GTA TPI they didnt have to, but I'm not sure about our LT1's.

 

You're checking for pressure leakage, so I don't see why the electrical connectors need to be on. You would just need to keep the rail pressurized with the prime connector wire while checking.

 

The easiet method would be to connect of fuel pressure guage, then turn the power on to your car to prime the pump. Then turn the power off. If your guage starts to drop after the power if off then you definately have a leaky injector...assuming your fuel lines/FPR are hooked up correctly.

To fugure out which ones are leaking, simply remove them one by one, until your PSI holds. I hope I've been helpful.