As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE FLIGHT FL270, THE LT ENG SLOWLY ROLLED BACK TO IDLE 58% N1. EMER CHECKLIST FOLLOWED. AN EMER WAS DECLARED & DIVERTED. LANDING WAS UNEVENTFUL. REPLACED LT ENG FCU, RIGGING ACCOMPLISHED & SUCCESSFUL OPERATIONAL CHECK FLIGHT WAS PERFORMED. ACFT WAS RTS.