Electrical Problems

[F23]

Hello Everyone, (posting here because this is my daily driver, and I need it running yesterday)
My '69 Cougar (identical to '69 Stang for this purpose) has been having these weird spouts of terrible running, popping, stalling, and fluttering for about a minute, then they go away... Weirdest thing. So I hook up a timing light to see if my distributer was screwing with the timing (just installed new one), and I realized that the light wasn't flashing regularly when the episodes occurred. Quickly, I ran and grabbed my volt meter and realized the voltage to the coil was fluctuating in-between 10v and normal voltage. When it normalized, so did the engine problems. I realized when I wiggled the wire, it would have another episode. Figuring a lose connection, I pulled the harness (which is is not to good condition), and replaced all of the wire up to the connector with new wire. Then I cleaned and reconnected, and tried to start again... A few minutes later, same episode. So I wired the coil directly to the battery and it STILL had the same problem! I'm completely lost. What could this possibly be?




Thanks,
F23