As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EXPERIENCED INTERMITTENT FIRE WARNING ON NR 4 ENGINE IN CRUISE UIO TO MIA AND NO OTHER INDICATION OF FIRE. INSPECTION REVEALED BROKEN GROMMETS ON FIRE WARNING LOOP AT LEFT AND RIGHT AFT COWLING, CAUSING INTERMITTENT GROUNDING. REPLACED FIRE LOOP GROMMETS. SYSTEM CHECKED NORMAL. AIRCRAFT RETURNED TO SERVICE. (M)