964T Ignition arc

[turbo ride]

Hey Guys-
So I think I know my problem (well my car's problem - I have lots of problems). Just can't nail it down. Here's the story:

1991 964T. Replaced cap, rotor, plug wires (and connectors), plugs last spring when I had the motor rebuilt. Have 5000 miles on car since. But note - 1500 miles after replacement one of the plug connectors broke (#2 IIRC). So a week or so ago after washing the car it started to miss on the drive home - felt like running on 5 cylinders (which I normally wouldn't mind if I were in a cool old-school Audi, but I wasn't, so...) and it would stumble a little with low rpm load.

So anyway a few days later it was fine. Did a 100 mile drive car ran great - until literally last 2 minutes - running rough like on 5 cylinders. Put the car on ramps had the wifey keep the engine at 3000 and used my temp gun to measure temps of exhaust ports into the headers - they were where they were supposed to be. No cold cylinder. Next day cold start runs great. For about 10 minutes and then rough.

Repeat - only this time I pop the lid and I can hear an intermittent ticking either at the coil or cylinder 1 or 2 and can actually hear it coincide with a minor stumble at idle. Sounds like an ignition arc ticking. So a little later when it's dark a get the engine arcing again - and I _think_ I can see a small spark - first down by the cap - but can't tell a specific plug. Then it looks like its actually in the coil itself. I spray water mist - doesn't help. But best I can tell it's arcing inside or at the coil. I happen to have a spare coil so I swap it in. No change. Then I pull the cap and look for moisture inside (mind you I had done a 100 mile drive since washing the car) - inside the cap it's bone dry. I do find the tiniest bit of moisture inside each plug lead at the cap. Wipe them all dry. Also was thinking it was maybe the coil wire itself - managed to destroy the actual coil wire itself while trying to twist the ends off - had a spare short wire so attached the ends to it. No change. ** I did notice that the ceramic bit on the coil wire on the end that attaches to the coil itself is yellowed / slightly browned..wondering if this might be from arcing..???

So bottom line I feel like I have an arc after there is some heat in the system - around the coil or cap or 1 or 2 plug - but how do I nail this down?

Thanks for any help

Brandon
'91 964T