I have a 1991 Mitsubishi Montero. It's in great condition. It had the motor replaced at about 150,000 miles, now has about 189,000 miles on the truck and around 39,000 on the motor. I purchased it about a month ago and drove it around 80 miles home. I then took it on a weekend trip of about 200 miles or so. It has demonstrated some electrical problems with the windows (back right window must be rolled up from back right door panel instead of master panel, sometimes windows short circuit and will not roll down or up). About a week after I got back from the weekend trip it sputtered and died on the way home so I ended up pushing it the last block or so.

I replaced the fuel filter hoping that was the issue. It wasn't, so I replaced the fuel pump and have put HEET in the tank to dissolve any water that might be there. It's still doing it. I can start it up and drive it for a few blocks then it sputters and dies again. It acts like getting warmed up is fouling something. I can put it in park in my driveway and rev it up forever but when I take it out it sputters and dies.

After it dies, it won't start back up for several hours (but it does start back up). I've heard it might be my distributor coil (whatever that is). I don't have any idea how vehicles work honestly. I'm competent enough to take parts off, put parts on, and diagnose a great many issues as I've driven a lot of beaters in my day, but I'm trying to keep this as a decent reliable vehicle.

I'm losing my mind here trying to figure out what's going on (and spending a fortune on parts). So any help is SO greatly appreciated.

A distributor issue sounds probable. I'd probably separate the windows issue from the spluttering one for now, I'd be very surprised if the two are in anyway related.

You might want to look at replacing the distributor cap. It could actually be breaking down under load meaning that electricity is travelling across it between spark plug lead connections when it gets hot. Seen it happen before. For that matter a new set of spark plugs leads are a good investment if you are looking at chagning the dizzy cap.
Both are easy to change, by looking at them you find the change self explanatory.

Don't know what a second hand distributor cap costs from a car junkyard / wrecker where you are but second hand in my part of the world about $15.

So for a new one from a spare parts dealer maybe looking at $30-40.

I ALSO HAVE A 91 MONTERO. THE MAIN WINDOW CONTROL WAS JACKED UP ONLY THE DRIVERSIDE WORKED UP AND DOWN. PASSANGER SIDE ONLY WENT DOWN. I CHANGED THE MAIN WINDOW CONTROL. I PICKED MINE UP FROM THE JUCK YARD AND IT FIXED THE PROBLEM. AND FOR THESPUTTERS AND DIES LIVE THE LAST PERSON SAID IT COULD BE THE CAP OR IT CAN BE THE ROTOR. I EASY WAY TO CHECK TO SEE IF IT BAD IS IF IT HAS A WHITE LOOKING BUID UP ON IT LOOK IN THE INSIDE OF THE CAP AND THE LIL GRAY METAL SQUARE PINS. IT ALSO MIGHT BE THE CATALYTIC CONVERTER. MIGHT START GETTING PLUGGED UP. HOPE THIS INFO HELPS