https://www.gmforum.com/trouble-shooting-test-procedures-141/testing-negative-battery-cable-279492/

If it didn't work on the car, but worked on the bench at AZ, then I am highly suspecting one of your cables.

Do you have a set of jumper cables?

Connect - to battery, and the other end clamped to the starter somewhere. Attempt to start. No change? disconnect the negative, now connect positive to the + battery terminal, now connect the other end to the starter solenoid post(the small one)

Let us know.

I will run the negative battery cable test later this week.

When I put my starter back on I noticed that the small post connection that the small nut goes on would not tighten up. Upon inspection, the small post seemed loose and not firmly connected to the starter. Is that a problem and what is the best way to fix that? Would I need to replace the starter after all. Thanks for all of the support!

Yes, that would more than likely be the problem. I had an issue with my 95 like that. I had to tear it all apart to tighten everything down.

That little post is on the solenoid. If it'* loose you will have to replace the starter. You can try to take it apart and tighten it up, keep in mind the post cover is made of a some what brittle pllastic that likes to break

Starter plastic is very brittle. I shattered my old (dead) starter when taking it out of the car. Fortunately, the guy at Advance never opened the box, so I still got my $12 core.

The starter solenoid is a separate and replaceable part on some years, but since you have to pull the starter anyway, it'* best to pony up the extra cash and get a whole new unit.

I did not replace the starter yet....just getting out of work. When this all started, I pulled the codes and got these 3:
34 MAF
42 Electronic spark timing circuit
56 Quad driver B fault

Is there any chance I have a PCM issue, given these codes?

They may have been history codes. Only way to find out is to disconnect the battery for a few minutes, reconnect and drive around for awhile. Then recheck for any new codes.