As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DUE TO INTERNAL LEAKAGE OF DIFFERENTIAL PRESSURE SWITCH, A LOST OF FUEL WAS HAPPENING THRU THE OVERBOARD DRAIN WHICH WAS CREATING A PRESSURE DROP IN FUEL PUMP SYSTEM, THE AUX PUMP WOULD THEN COME ON AND OFF THUS CREATING A SMALL FLUCTUATIONIN THE ENGINE PARAMETERS. AFTER INVESTIGATION AN IMPROVE SWITCH WAS MADE AVAILABLE THRU SB73-011 DUE TO IMPROVED RELIABILITY. THE OLD PN 8346 CAN BE NOW IMPROVE BY USING PN 8346-001.