Just a note on electrical connections. The terminal designs on early Japanese cars are really bad. They have no water seals and the connecting pins corrode and come loose with age. They are a constant source of misery on these older cars.

 

If you do not care about period correctness, but want a more reliable car, I would strongly suggest changing the electrical connections in the engine bay and exterior lighting etc, to Weather-pack or Deutsch connectors.

 

Deutsch connectors are more compact and easier to assemble than Weather-pack and are available in many configurations and amperage capabilities. They are a preferred electrical connection on many Race cars including Nascar, IMSA. NHRA and Off Shore Boat racing. 

Yes, that seemingly unnecessary short intermediate piece of wire is a fusible link. If it's like mine... Take a close look at it, you'll see that it is actually just one wire. I think the other "wire like thing" that runs between the two connectors is a piece of solid plastic cord to act as a strain relief to reduce mechanical damage to the link itself.

 

Another important place to clean up is the four fusible links in front of the battery on the passenger fender well. One of them is related to the EFI system as well and if it's intermittent, it could cause your symptoms.

 

Here's a basic Classic Z Car repair axiom... You get a spare moment, clean some connectors.

 

Even if something is functioning correctly (today), you have time on your hands? Clean some connectors. 

Don't forget the black ground wire.  Similar area, but connected to the negative post, and no fusible link.