As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF RIGHT ENGINE SURGING N1 +/- 10 PERCENT. ALL OTHER ENGINE PARAMETERS ALSO FLUCTUATING. DECLARED AN EMERGENCY AND RETURNED TO JFK. LANDED OVERWEIGHT. MX IN PROGRESS. PIMU FAULT 352-15A/B AND EEC CONTROL MSG. REPLACING CIT SENSOR, N1 PROBE AND PERFORM HPC BORO.