As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE RUNNING UP AIRCRAFT AFTER MAINTENANCE, IT WAS NOTICED THAT THE FUEL QTY GAGES WERE JUMPING FROM FULL TO EMPTY AND THE LOW FUEL LIGHT WAS FLASHING. BOTH TANKS WERE FULL AT THE TIME. INSTALLED NEW SENDING UNITS IN BOTH WINGS AND IT SEEMED TO REMEDY THE PROBLEM.