T.
The first thing that came to mind is the circuitry under the distributor.
There exsists some wires whose insulation become crumbly. Easy to verify.
Be very careful taking the plug off due to how delicate this area becomes
with age.
The next item I would check is the idle position sensor. You should hear
an audible click every time the throttle opens and closes.
Good luck,
Ken Lewis
http://neksiwel.20m.com/