As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT 3054, DURING TAXI OUT PILOTS NOTICED EXHAUST SMELL ON FLIGHT DECK. INITIALLY THOUGHT IT WAS AIRCRAFT IN FRONT OF US. CALLED FA'S AFT FA'S REPORTED BURNING PLASTIC WIRE SMELL IN ROWS 36-37. PILOTS DONNED O2 MASKS, RETURNED TO GATE. AFTER GATE ARRIVAL AND ENGINE SHUTDOWN REMOVED MASKS AND SMELL WAS GONE. CORECTIVE ACTION: REPLACED PED OUTLET AT 39AB. (LP 5863934)