Flight Crew Last 90 Days 222; Flight Crew Type 8000
Confusion; Distraction; Situational Awareness
Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance
General None Reported / Taken
Aircraft; Weather; Human Factors
Aircraft was written up on the previous leg for inoperative Vertical Speed mode during autopilot use. On departure this leg; Tower advised to stay with them for numerous heading changes. Climbing through 1;000 feet AGL; Tower advised new heading which we turned to; still in Takeoff Go Around (TOGA) mode manually flying with autothrottles on; we cleaned aircraft up; continued climb toward 3;000 feet MSL. There were moderate turbulence encounters from there until cruise altitude. Passing 2;500 feet MSL; Tower advised us of a new heading which Pilot Flying (PF) turned to; passing 2;700 feet; Tower advised yet another heading and gave new frequency. Passing 2;900 feet; the autothrottles started to retard for the TOGA speed and Altitude Acquire Que. At 2;950 feet the flight directors started to direct a descent and I noted PF following them I advised 'you are sinking start a climb'. At 2;800 feet we again were in a climb toward 3;000 feet.  At 2;900 feet PF engaged autopilot; I noted Altitude Acquire; CMD B presented autopilot engaged; autothrottles engaged; aircraft overshot 3;000 feet passing 3;100 feet and continued to climb.  I advise PF to correct.  PF disengaged autopilot and corrected back but not before we reached about 3;275 feet MSL. Back at 3;000 feet; autopilot was engaged with no further issue. ATC did not mention altitude deviation. We both thought this might be related to the previous Vertical Speed failure writeup; but that was not verified and it appeared the winds there were causing issues with the autothrottles input and FD commands during Altitude Acquire.
A B737 Captain reported flight director and autopilot anomalies during altitude capture with an inoperative autoflight mode.