Hi,

Yikes! That is some really old fuel!

You might want to give that car some vitamins to help the zap the fuel system into a cleaner condition!
I’m thinking a can or two of ChemTool B-12!
Get the type that pours into the tank. It may help dissolve the gelatin balls or slime in the tank.
The detergents, in the Tiers 2 gasolines, might not be all that fast!
It again, is Depending on you wanting too, wait it out?

You might want to check out how old the timing belt is or at least quickly readjust the tension on it!
This car has been forelorned, so that means, numerous things under the hood are likely stale, in like, all the rubber vacuum goodies!

I bet the battery has suffered too.
If you haven’t replaced it, think about it, as probably, it has sulphated greatly! That is internal created damage and shortens their lives dramatically!
If you are planning a habit of leaving this car to sit some lengthy amounts of time, that will make the battery raise up its ugly head sooner!
Explanation is, If and when recharging up battery, it happens to rise very quickly or one that fails to hold charges regularly, gets coupled with today’s electronic sensitivities, you are then rolling dice, against odds of reliability and it purring like a kitten every happening

Good thing you are willing to give it some up graded TLC,

Phil