As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE TAXIING OUT FOR TAKEOFF, SEVERAL OTHER PILOTS FOLLOWING OUR AIRCRAFT, REPORTED SEEING A 3 TO 4 FOOT ORANGE FLAME EXTENDING AFT OUT OF THE EXHAUST AREA OF THE NR 1 ENGINE WHEN ENGINE POWER WAS PUSHED UP BEYOND IDLE. FLIGHT DECK ENGINE INSTRUMENTS WERE NORMAL. ACFT GROUNDED. REMOVED AND REPLACED THE NR 1 ENGINE LUBE UNIT IAW AMM 79-21-01-000-801-F00, AND 79-21-01-400-801-F00. LEAK AND OPS TESTED GOOD.