What was found
FLIGHT 3760, DIVERTED DUE TO SEVERAL PASSENGERS DETECTED A BURNING ODOR THROUGHOUT CABIN, PILOT ALSO DETECTED BURNING ODOR COMING FROM ALL VENT UPON OPENING COCKPIT DOOR. EMERGENCY WAS DECLARED AND THE PASSENGER COMPARTMENT WAS PREPPED FOR SAME. AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED BOTH ENGINES AND APU. MAINTENANCE FOUND NR 2 ENGINE OIL OVERSERVICED. APU BLEEDS WERE RAN AND AIRCRAFT ENGINES WERE RUN INDEPENDENTLY, NO BURNING ODORS NOTED. AIRCRAFT RETURNED TO SERVICE.