Toyota 86 turbo, misfire under load

Im having a problem with my Toyota 86 that I turbo. The ignition brakes down under load on one of the cylinder, I can hear and feel that its running on 3 cylinders when it happen and holds back. It happens only when engine is under load and you put your foot flat, the miss is always at around 3800rpm. If I lift off slightly the power comes back. If I pull the engine from low rpm in a lower gear with less load it runs clean and strong all the way to rev limit..

Boost is 0.7, std plugs and coils. I did replace plugs and that didn’t help. I then closed the gap on the center electrode to 0.6mm (the plugs have 3) this improved things, it now doesn’t breakdown every time I load the engine but still does it at intermittently . No fault codes or engine light coming on.

Im wondering if increasing the dwell time would helpp?

Has anyone had similar issues with the 86 ?

It there a need for a upgraded coil packs and should I change to a different plug.

We're running stock coils in a turbo 86 that runs 13-14 psi on E85 and makes around 380-390 whp with no issue so the stock coils are definitely up to the task. We are running an HKS spark plug that's a little colder than stock but we had previously run the same boost with stock spark plugs s they are still up t the task. That's not to say that you don't have a faulty coil though - It would be unlikely but nt impossible.

The other situation that presents as a misfire is leaking DI injector seals. I've seen this on a couple of local 86 race cars and it normally results in what seems like a misfire at low rpm.