<VV> Engine miss?

[Grant Young]

Hello. Just finished helping out a new Corsa 180 owner with a persistent engine miss by replacing a bad coil. Car runs fine until the boost gauge starts going positive and then we get a high speed miss (noting like with the bad core, but noticeable. Has a newly rebuilt carb, tight turbo charger, good rebuilt correct distributor, new plugs and wires. Where else should I look?
Thanks,
Grant