This is about the second most common question on this forum from newcomers so normally I would tell you to do a search but give the standard top three offenders (Fuel Pump Relay, Power Stage, poor fuse connections)...but you added a wrinkle by saying it is carb car. Never heard of an '87 without FI but I am sure they exist in some markets.

I suspect the ignition system still uses the EZK or similar ignition system so I would still check the powers stage.

A full fuse box service is still in order unless you have done one in the last year. This means removing all fuses, clean the clips with a green scrubby or similar, re-install fuses replacing any plastic and lead fuses with brass and ceramic and finally re-tension any fuse clips that are not holding the fuses tightly.

You do all that because you cannot look at one of these fuses and say it is good...until it is out of the fuse holder and in your hand, you cannot assess its condition, but everyone still insists they can.

The fuel pump relay could still be an issue but with the much lower current requirements of the low-pressure pump, I would assume they just use an ice-cube relay instead of the more complex ones on the FI cars.

This is good mystery and I look forward others responses. Invariably they will tell you to figure out if you are losing spark or fuel so I would suggest finding a way to verify spark while going down the motorway.