I agree.... fuel or fire.

Can you log the runs?
"Sounds" like a coil/spark issue to me. What kind of spark management is it? Does one coil fire all cylinders, or does it have individual coils for each hole?

Where's the fuel cut-off/ limiter set at(rpm)?

Run a cheap mechanical FP guage off your rail to the cowl, and see what it looks like at whatever rpm it's dieing at.

You hearing any audible detenation at that point? If your FP was dropping bad enough to kill power like that, I would think you'd hear some knock before it nosed over(lean as piss).

With EFI, it would be hard for a fuel issue to kill all the cylinders the way it's doing unless it was a pcm issue.

You really need to log a pass to be sure which, but I still say spark. I've seen coils that run/fire perfectly fine in the midrange and stutter up high.

Good luck-