A310 not following flight plan

Hi,

Thank you very much for the taking the time to reply to my enquiry. For sure there is a major improvement meaning the flaps/slats do not move anymore while taking off from the runway and in the 2 test flights that I have done i noticed the plane stays the course and does not deviate. One little quirk I noticed while on approach with glide slope and localizer both locked in, when I disconect the autothrust the plane is doing 2 things: tends to pitch up and always the manual throttle control does not seem to be linear. Meaning I move the throtthe just a bit up or down trying to keep Vapproach speed constant but the throttles seems to be moving very aggresive. Any ideas?

Thanks