I highly suspect that on that age of a vehicle the starting issues are related to possible a bad gas filter but also corroded or rusty connections in the charging system the fuse box, power junctions, battery , alternator , starter , engine block ground posts and other grounds , plus any plug in connectors or connections. Remove each one one by one and clean them with a wire brush etc and if you or a friend can't do these things has a reliable mechanic them but be sure to out line and tell them all the work you want performed.
It also be a good idea to have a free charging system test performed so you know the battery , alternator etc are working.
Be sure you test the fuel pump you should hear a buzzing sound coming from it but you might need to remove the gas gap to hear it better.It could be that the pump is dry and takes time to finally warm up and kick in, so one test you can try is leave the ignition in the run position for 5 to 10 mins then try starting it and if it starts right up either the fuel pump is bad or you could have a really dirty gas filter or the fuel pump relay might be acting up on it too.
One test is the buzzing , another is touching the relay see if it vibrates or is buzzing slighty that says it's supposely working but remember a relay could be internally weak or faulty so when in doubt try another one in it's place.
Hope that helps and best of luck.By the way even bad spark-plugs or spark-plug wires or bad connections on the ignition module for the spark-plug wires can cause starting issues or be part of the problem.
Even after you have this done I'd highly recommend if at all possible you have the starter removed and fully tested via a starter rebuilder shop or parts outlet etc.The charging system test and starter draw test is okay but at times it's best to have the indivual components such as the starter tested off the vehicle seperately.
One last suggestion have the charging system , gas filter , work done and try to make sure you've a totally fully charged battery in it , one way is driving a good 10 to 15 mins at hwy speeds, personally I like to remove the battery then take it test it as it fully charges up , then if starting issues see later how much the battery has drained bec that indicate poor charging system connections or a starter that is drawing too much amps.Note dont try starting any vehicle longer then 10 seconds at any time then wait a bit before trying to start it again , this will save your battery , also it will keep your starter from burning out and less chances of fluiding the engine too, plus you could burn out your ignition otherwise.
