The octane rating of the fuel may be part of it. Do you have a wideband oxygen
sensor, contrroller and datalogger? That might help determine if it is fuel
related. It isn't cheap, but it seems to help with diagnosis and tuning.
Anyway,
How do the plugs look?
What are they gapped at?
Type
What about the coil crapping out at higher boost.
What coil are you running?
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