As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 2496 - EWR - CREW REPORTED ENGINE NR 1 SMOKE COMING OUT FROM THE EXHAUST AND CONTINUING FOR 15 MINUTES AFTER SHUT DOWN ON TAXI IN. EWR MX PERFORMED OPERATIONAL CHECK OF NR 1 ENGINE (HIGH POWER RUN) AND COULD NOT DUPLICATE THE PROBLEM. ACFT WAS APPROVED TO RETURN TO SERVICE.