As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT, FLAMES FROM THE TAIL PIPE OF NR 1 ENGINE WERE REPORTED. MAINTENANCE INSPECTED THE NR 1 ENGINE AND FOUND OIL IN EXHAUST PLUG AREA WITH NO DETERIORATION OF THE HONEYCOMB. ACCOMPLISHED RUN OF NR 1 ENGINE WITH NO FLAMES OR SMOKE NOTED. ENGINE FOUND SERVICEABLE IAW AMM 71-00-00-800-803.