As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
R ENG FAN VIBRATION CYCLED CONTINUOUSLY BETWEEN 0.0 AND 5.00 ON TAXI OUT AND RTN TO GATE. NO VIB WAS FELT. ENG WAS STABILIZED AT IDLE. INSP INLET AND EXH AND CHIP DET. FWD TO MCO AND PLACARD. T/S PER FIM 77-31-00 FIG 103. PERFORMED AVM BITE PROCEDURE. ALL CHECKS NORMAL. A/C OK FOR SERVICE. MCO AND PLACARD REMOVED.