Volvo Repair: intermittent starting problem, volvo 740 gle, fuel pump relay

Question
my son has a '87 Volvo 740 GLE with 200m miles.  We have put some money into it only because the engine is clean and runs great.  Just recently it has developed an intermittent starting problem.  It died while my son was driving once and now sometimes it won't start.  If we wait a while it will start.  I have pulled the coil wire and spark plug when it doesn't start to check for spark.  It doesn't seem to have spark when it doesn't start, but I'm not 100% sure.  So far I have replaced the wires and I have replaced the coil.  It still does the same thing.  The Volvo dealership suggests replacing the distributor.  Is there a better way to find the problem.  When it runs, it runs like a champ!
Please help if you can.

Thank you,
Bill

Answer
  Bill,

         The hardest diagnosis is intermittent no-start problem...
        Consider the following:
        Volvo's have had minor problems in the dist. area.
        Check your fuel pump relay.
        Check fuses and connections.
         Replace fuel filter.
         Buy a used dist.
          Blocked cat.converter

       Hope that Mercury leaves retrograde.

      Good luck,

        Bilbo