Golf VR6 - Coil Pack - Intermittent Fault

Hi

I changed the coil pack on my VR6 back in January. Plug leads were changed a few months ago as well. Car has developed a fault on cylinder 1. Misfire. When its happening I can pull off the plug lead at the coil pack end and there is no spark. All other cylinders are fine. Trouble is - the problem comes and goes. I'll drive the car on a journey, with the misfire. Next time I start it up - its gone. When its gone, there is a good spark when I pull of the lead on the coil pack end.

What's happening? My presumption is that the coil pack is failing - but intermittently. Is that possible?

As the plugs hadn't been changed in a while, I changed them today for a new set of NGK platinums. Car is running really smoothly now on them. Thought maybe it had cured the misfire. But no - it appeared again. Pulled of the plug - no spark. But then as I was fiddling, it sparked. And started to run smooth again.

It all points to the coil pack surely? I've bought a replacement from GSF where I got the other one. However I'm reluctant to change it over and send the other one off under warranty as if the fault is intermittent, then it may appear fine when they test it. And I will lose my money.

Any thoughts?

Paul