1994 Pontiac Transport motor cuts out.

Does it immediately start back up?

Then it's going to be very difficult to find. Certain functions have to be monitored DURING THE FAILURE only. This will not be easy to accomplish. Simply throwing parts at it will only serve to empty your wallet.

Believe me, these are issues that we deal with every day and it can be very difficult.

The things that need to be monitored are fuel pressure, spark and injector pulse. They have to be observed at the very moment it dies to see which one drops out first. There are ways for us to do this but you are not equipped for this. The possibilities are endless and expensive so throwing parts at it should not be an option. You can spend twice what the car is worth and still have the problem.

I have never heard of a "rebuilt" fuel pump and honestly, it really doesn't sound like a fuel pump issue. You would have more symptoms just before and just after the failure. I would be thinking more on the lines of Ignition Module, Engine Control Module, Crank sensor, etc but again, you don't have enough evidence in any direction to justify the expenditure.

I don't know how valuable that 6 month warranty would be to me since it requires removing the fuel tank to change the pump and they don't cover that and again, there is no such thing as refurbished. That's a fancy name to call a junkyard part that has been sitting in a scrapyard in stale fuel for what could be years.

There is no way to test a working crank sensor. It can only be tested during that split second when the engine dies so you see how hard this can be. Your trying to tackle something that some of the best techs around would struggle with because you simply can't fix what isn't broken and that is the condition whenever the tech would examine it.