What was found
IN CRUISE SMELL OF SMOKE AND THE SIGHT OF SMOKE COMING FROM BACK OF S/O PANEL. SMOKE MOVED TOWARD F/O SEAT. THE SMELL WAS LIKE CAR EXHAUST. RAN ALL FUMES AND ODORS CHECK LIST. ALSO SHUT OFF GASPER FAN. THE SMOKE ONLY LASTED FOR AROUND 15 SEC. NO OTHER INDICATIONS. REPLACED APU C/B REF MM 24-20-041-4. REINSTALLED ALL REMOVED ITEMS FROM F/E PANEL REF ESP MM 20-46-50 AFTER VACUUMING DEBRIS AND DUST. RAN ALL THREE ENG'S, OPS CK'D ALL REMOVED ITEMS. OPERATED PACKS AND GASPER, CK'D ALL PANEL LTS AND TRANSFORMERS. NO ABNORMALITIES NOTED. CLEANED WIRES AND TERMINALS TO C/B. REMOVED IDENT MASKING TAPE. INSPECTED AREA FOR OTHER ARCING OR WATER DAMAGE. ALL OK.