RE: mvvs 58 limited edition
Steve, can you give me some more information?
What prop do you run (size, wood or carbon) Still on Xoar 24x10 wood?
are the M5 bolts tight (not bottomed out) Torque to at least 3 Nm, check torques every day!
Is the central bolt nut snug (not too tight please or you will ruin the prop and prop drive)
The woodruff key should not be visible. Something may have happened when the prop was loose, or the central bolt has been overtightened.
Midrange misfiring also leads me to think you have a loose ignition power connection somewhere, that acts up due to vibration in certain ranges. The fact that it now spreads to full throttle supports that thought.
Take out the engine, and thoroughly check the prop drive and ignition leads. Also check your ignition switch and all leads. If in doubt, exchange.