The jy is a solid source for inexpensive computers. Depending on your transmission, you may find a few of them for less than 50 bucks.

Well, got the PCM fixed up and put in. The battery was drained completely so we had to leave it on the charger all day. Came home and tried to start her up...fired right up, but started to idle rough so I gave it gas. After a little bit of the rough running, she smoothed out. Left her running for five or so minutes, sounded great. I decided to shut it off and try starting it up again, but now we're back to the cranks but won't start except when I put the pedal to the floor. Even then, it starts but dies right away. Any ideas now?

What's your fuel pressure immediately after shutdown?

PSI is 38 immediately after shutdown.

Does it hold 38 for an extended period of time?

Yeah it holds 38. We checked the timing and it was perfect. We are at a point now that it starts, and will run without dying. But it is extremely rough.

Can you refresh in a single post what you've done so far?

After replacing the harmonic balancer and crankshaft bolt that busted off, the truck ran rough and eventually would not move. We then tested the fuel filter to make sure it was not clogged. After that, we changed the pressure regulator. Then, we changed the fuel pump. Before we changed the fuel pump, the PSI was around 24. After we changed it, it stays around 40 PSI so that did help. After that, we checked fuses and relays. We were able to get it started with starter fluid, but it would die immediately. Then we replaced the throttle position sensor. We checked for spark and that was fine. We tried pulling codes, got a 512(Keep alive memory test failed) and that is all. We then replaced the PCM because it had power to the pin and it had a lot of corrosion on the capacitors. Once we changed the PCM, it does stay running but it is extremely rough. Not enough to actually drive or anything.Then we checked the timing and it was perfect.

About the only thing left is the MAP sensor, ECT and ACT sensors.
Check the vacuum line to the MAP sensor also.
The MAP, ECT and the ACT sensor can be bad but you will not get any codes for them if the Computer does not understand that they are bad. But you can test them.

You might also try blocking off the EGR valve until you get it going.

Does it run better on starting fluid, or the same?

I.e. does it run smooth at any point when running off starting fluid.

Where are those sensors located? And how can we test them? We were thinking about testing compression next.

Also, it runs the same with starting fluid. Real rough.

Note the MAP sensor can also be tested with a hand vacuum pump and a Dwell meter or a Frequency meter.
See attached PDFs for testing.
The location depends on what engine you have as you have not stated the type.

We'll try testing those tomorrow. It's a 5.8l 351