What was found
ON 01/01/2013 DURING TAKEOFF PILOT NOTICED ENGINE RUNNING ROUGH, RETURNED TO AIRPORT FOR LANDING. (NO EMERGENCY DECLARED) ON 01/02/2013 A MECHANIC INSPECTED THE AIRCRAFT AND SUSPECTED FOULED SPARK PLUGS, AFTER CLEANING SPARK PLUGS THE MECHANIC TEST RAN THE AIRCRAFT NO ABNORMALITIES NOTED. ON 01/03/2013 PILOT RETURNED TO THE AIRPORT AND TEST FLEW THE AIRCRAFT, THE AIRCRAFT RAN FINE ON RUN UP BUT AFTER TAKEOFF STARTED RUNNING ROUGH AGAIN PILOT RETURNED BACK TO THE AIRPORT. (NO EMERGENCY DECLARED) MECHANIC REINSPECTED THE AIRCRAFT ON 01/04/2013 AND FOUND THE NUMBER ONE CYLINDER FUEL INJECTOR BROKEN IN HALF.