Fuel Injector overspray

I am unable to get my Olds to start up. In trouble shooting the issue, it was clear I was getting spark and fuel, but it appears the injector was spraying too much fuel into the system, flooding it.

When the key is in the on position, not cranking, the injector is spraying a constant "shower" (not a light mist) of fuel into the throttle body. This fuel spray continues until we crank it. No start. As I turn off the ignition the injector acts like a toilet and continues to shower nearly a 1/4 cup of fuel onto the closed butterfly valve.

I have switched out the injector and the engine turned right over. As soon as I turned it off and tried to start it again the problem returned.

As I studied further I realized that with the ignition in the On position there is an inconsistent rattle/clicking sound coming from the injector, and I can feel a vibration in the injector in time with the rattle/clicking noise.

I unplugged the injector electrical wires and tried cranking the engine. The was no clicking noise or vibration. With the key still in the on position I plugged the wires back in and the rattle/clicking and vibration DID NOT return. I was able to start the engine and it ran smooth for over an hour.

I turned the engine off and let it cool. When I went to turn it back on, as soon as the key was in the on position, prior to cranking, I could hear the rattle/clicking sound and the engine failed to start, and the excessive fuel shower returned.