I don't believe the Jimny has any specific problems in this area, but I have to be honest and say I don't have any direct experience on the early Jimny engine.
That said I have plenty of classic cars with rotor based ignition systems, so if that's what you have this may help.
Normally I would suggest checking or replacing the plugs, leads, rotor and cap as a first pass, but it sounds like the PO has done this already. I assume it has solid state ignition? If not you have points as a condenser to consider.
Still worth giving it a once over if you have not done so already.
Your description makes me think it's only missing on one cylinder, if so try to find which by removing spark plug leads one at a time. If it runs worse that's a good cylinder, no real difference suggests it's the faulty cylinder.
Once identified or even if you can't try to do a cold compression test. The overall pressure readings are unimportant, but they should all be similar. Any reading different could suggest bore, valve or head gasket issues. You can test further to determine which, but not worth explaining further until we know you have the tool to do a compression test.
If your miss fire is on random cylinders then it suggests a common issue, ignition or fuel and could be the items you suggest.
So give it a once over and try to confirm random or a specific cylinder miss fire.
Good luck, sure more suggestions will follow.
Mike
Not 100
Yokohama Geolanders, Sony head unit, NAUTILUS Air Horn, DRL conversion, Rear cargo space, Elvis Bobblehead, transfer Guard, Indian hanging Elephant, Koni Heavy track dampers, Custom SS exhaust, Voodoo Doll, Adventure Rack with LED ight bar, vintage ERIBA caravan usually attached (yes it's slow)
