As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ENGINE REPORTED RUNNING INTERMITTENTLY. MIXTURE OPERATES ONLY THROUGH LIMITED RANGE. INSPECTION REVEALS LARGE MOUSE NEST IN AIR BOX AND CARBURETOR AS FAR AS VENTURI. SEVEN DEAD INFANT MICE FOUND IN NEST. ENTRY TO CARB THROUGH CABIN HEATER DUCTING. AIRCRAFT LAST FLOWN APRIL 3, 2004. SOLUTION: ENSURE CABIN HEAT CONTROL IN CLOSED POSITION.