What was found
AIRCRAFT HAS PITCH OSCILLATION (PORPOISES) WITH ANY AUTOPILOT IN COMMAND AND (V-S, ALT HOLD, VNAV, FLCH) MODE SELECTED. REPLACED LOWER RT ADC. PERFORMED THE FOLLOWING: HOOKED UP AIR DATA TESTER TO LT & RT ADC'S. APPLIED PRESSURE FOR 5000 FT & 250 KTS, THEN 15000 FT & 250 KTS. CAPT & FO'S AIR DATA INSTRUMENTS AGREE. RECONNECTED HOSES TO ADC'S THEN CONNECTED TO PITOT PROBES. PERFORMED 5000 FT LEAK CHECK & FOUND LOWER RT PITOT (AUX 2 PITOT) LEAKING. REPLACED LOWER RT PITOT PROBE IAW MM, PITOT LEAK CHECK OK, ACCURACY CHECK OK.