As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - ON FLIGHT NUMBER 2555, ON CLIMBOUT, NR 1 FAN VIBRATION ROSE ABOVE 1.7. AFTER LERCHING AT 29,000 FT, AIRCRAFT COULD NOT MAINTAIN CRUISE SPEED WITH POWER SET TO KEEP FAN ON THE GREEN ARC. FOUND ONE BLADE TIGHT. LOOSENED AS REQUIRED. GROUND RAN AIRCRAFT WITH NO DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.