Autolite xp iridium from zzp. I had the plugs gapped at .50. But was told with such high boost I would get blow out. They said .32 would be best. Either way why only on the back 3 cylinders? They are all gapped the same. I will look at swapping the plugs for sure. Appreciate the ideas. No thoughts on the cam sensor? Crank sensor? Only codes I ever get is po300 and it's rare, but the misses are pretty much constant when warm.