Phenomenon known as 'pitch bumps, documented in 727maint manual as a service bulletin I seem to recall. Delving deep now but probable causes either: elevator lvdts (pcu change maybe), stab trim pot, pitch channel comp, a-p pedestal controller, and a couple that escape my memory. You trying to fix it, or just sick of feeling queasy?! Was a mech at LHR for PanAm/Ual and encountered problem a few times. Lvdts most probable, then pedestal ctrllr.
Or then again it might be something completely different!!!!
Happy hunting...............
Threestable.