What was found
AFTER LANDING AT THE DESTINATION AIRPORT, THE FLIGHT CREW REPORTED INTERMITTENT ENGINE VIBRATION IN CRUISE FLIGHT. A MAINTENANCE CREW WAS SENT TO INVESTIGATE BUT COULD NOT DUPLICATE THE ISSUE. ACFT WAS BROUGHT BACK TO HOME BASE WITH SOME INTERMITTENT ROUGHNESS/VIBRATION NOTED. SUBSEQUENT GROUND RUNS INDICATED THAT THE VIBRATION WAS FROM THE LT ENGINE AND IT WOULD NOT IDLE ON THE LT MAGNETO. THE MAGNETO WAS PULLED AND FOUND THAT THE DISTRIBUTOR GEAR FINGER WAS LOOSE WITH APPROXIMATELY .1250" MOVEMENT AT THE TIP OF THE FINGER. THE 3 REMAINING DISTRIBUTOR GEARS WERE CHECKED AND IT WAS FOUND THAT 3 OF THE 4 WERE LOOSE.