spark plug wires help

if there is one older ht lead (Spark plug lead) that is probably your problem as the old one is getting worn up as it is always a good idea to change ht leads from time to time sometimes you can get more power from an old engine by changing the plugs and leads so change all the leads for a new set if problem persists check spark plugs for sparks then check leads as described earlier and then check distributer keep working your way back until you find the problem but replace the leads first