I agree with 48bigtrucks. First find out if you can isolate it to a specific cylinder. Then I'd pull the plug and take a look at it. You might even consider switching the wire to another cylinder to see if the miss changes to it. I have seen MANY New plug wires, and plugs that are bad. Inspect the distributor,INSIDE, very carefully for possibly a crack. IF and WHEN you can isolate it to a specific cylinder then the cure is a lot easier. Let us know what you find.