Went through the same with mine, and initially things were pointing to the PCIII, JHP spent god knows how many hours (and at the drop of a hat - top service as ever) looking at mine, unplugged the PCIII and voila sprang into life, had it running for a good hour or so and didn't miss a beat. Then John pointed out that the PCIII only does fuel mapping nothing more nothing less, soon after she started playing up again, eventually both coils replaced, PCIII re-connected - problem solved