Car cuts out while driving

The place to start is by reading and recording the diagnostic fault codes. Here's a link on how to do that yourself:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

The most likely suspect, based on the intermittent nature of the symptoms, is the pick-up assembly inside the distributor. The problem is there is a computer module in there too, and another computer in between. Any of those can be intermittent, and there really isn't an easy way to narrow it down. It is just as likely there are corroded terminals in a connector that are making intermittent contact.

We never like to throw random parts at a problem, but in this case, I would consider popping in a complete rebuilt distributor.

Around this time period, GM had a lot of Engine Computer trouble too. You might try tapping on it to see if the engine stalls when you do that. If it does, remove and reinstall the plugs a few times. That will scratch shiny new areas of contact if there was some light film of corrosion on them. There is also quite a bit of history related to rusty or loose grounds. That should be less of a problem on Corvette bodies, but consider following the ground wires from the Engine Computer, and be sure those are clean and tight.

Keep me posted on your progress.

What do you mean by "replacement" and why is that different than a rebuilt unit? It sounds like you're expected to transfer some parts from the old distributor to the new one.

On '95 and older models, the efficiency of the catalytic converters is not monitored, so you can't tell if they're burning unburned fuel vapors properly. What you need to do is observe the readings of the oxygen sensor(s) to get an idea of what the fuel / air mixture looks like. The confusing part is if you have a spark-related misfire, you're going to have unburned fuel and air go into the exhaust system. Oxygen sensors only measure unburned oxygen, and will report an excessively-lean mixture. You'll smell the unburned fuel at the tail pipe as a rich condition. To aggravate the issue, the Engine Computer will respond to the apparent lean condition by increasing the amount of fuel from every injector. No matter how much fuel it adds, there will still be that unburned oxygen saying the mixture is still too lean.

You need a scanner to view short and long-term fuel trim numbers. If they are high positive, the computer wants to see more fuel go into the engine, even though there's already way too much unburned fuel coming out.

A plugged catalytic converter can cause an engine to stall, but it is going to gradually lose power and run slower and slower. You'll hear a hiss from the tail pipe instead of the normal "putt putt". It will sound similar to what it sounds like when you hold your foot, (shoe) over the end of the tail pipe. If an electrical problem is causing the stalling, it will be sudden, similar to turning off the ignition switch.

People have reported solving intermittent stalling on GM products by cleaning and tightening ground wires for the Engine Computer. The Engine Computers of this era caused a real lot of problems too for GM, so don't overlook those. Both usually cause a sudden stalling, but those types of causes can cause a sputtering for a few seconds before the total stalling occurs.

I have a Monitor 4000 that would work on your car with the standard "Chrysler / Ford / GM cartridge. Later I bought a Chrysler DRB3 because with an extra plug-in card, it will work on all of my vehicles back to '83 models. A lot of repair shops bought those because with that same card, it will do emissions-related stuff on all car brands, but only on '96 and newer models.

The reason I mentioned that is because the dealer-level scanners have been replaced by newer stuff, and a lot of shops are willing to sell their older equipment. You might stop in and ask around at a few shops. The dealer-level scanner for your car is the Tech2. I didn't use that one very much, but its operation was very similar to the DRB3. You might look on eBay too for a Tech2, but be sure they specify it will work on your year and model.

One of the most popular aftermarket scanners is the Snapon Solus Edge, but Snapon is one of those companies that has very customer-unfriendly business practices. I was going to buy one for my newer truck that the DRB3 doesn't work on, but I learned the annual updates are unreasonably expensive, and you can't skip any years. If you want to update it to the latest software version, you also have to buy every other annual update you're missing. Most other scanner manufacturers include all the latest information in every update, so you can skip three of four years if you want to. Of course, with the Snapon scanners, if it has everything you need, you don't have to have it updated ever, but they lose their resale value very quickly if you don't. The scanner costs $3900.00, but the updates are $1000.00 per year!

You might look for the guys who visit the repair shops each week with the tool trucks. Ask what they have in the "used drawer", or what they have available at home. Sometimes they have a sale pending for a new scanner dependent on them finding a home for the customer's old equipment. The popular tool trucks are from MAC, Matco, and Cornwell, as well as Snapon. Any mechanic can tell you when their salespeople show up. Be aware though they are usually only there for an hour, and some shop owners only allow them to visit, (cut into their customers' time), during lunch hours or mid-day breaks. You might have to wait until their business is done.

If you only want to use it on an '89 model, search on eBay for a Snapon MT2500. We called that the "red brick", because, ... Well, ... It looks like a red brick. Those were updated by buying a newer cartridge, and you'll find those all over the place. This scanner uses two plug-in cartridges at the same time. You'll find a lot of these listed for sale, so you'll be able to get an idea of their current value, and what to offer for one at a local shop. You'll usually find a bunch of these on Craig's List too. An often-overlooked place is the government institution auction sites. Community colleges list a lot of stuff on those sites. My Automotive program had two MT2500s but they were sold on auction a few years ago. I watch every day on a site called "Public Surplus". Mainly I've been searching high and low for a rust-free '88 Dodge Grand Caravan with 15" wheels, but I see scanners listed all the time. The disadvantage on this site is you usually have to drive to the place and pick up your treasures. Very few state they will pack and ship items.