Etlsport,
can only make an educated guess without a lot of diagnostics, but it sounds like your alternater, or voltage regulator, might have farted a voltage spike and caused your ECM to shat itself.
You would need to have a scan gauge connected while running and problem occuring. If I am right, the readings would be all over the place, if there at all.
Running ok below 2500 RPM sounds like a limp home mode built into most ECMs.
Good luck, and please keep the fam informed.
PK