GACFaja, just wondering, is it fixed? I have one E model that's got me bald after pulling all my hair...(not really, I shave what little hair grows) This one is intermittent and as far as I know it only porpoises on alt hld. I flew in it a few times this last two days and saw it abruptly porpoising on alt hld. Basic A/P was ok, as soon as alt/hld was engaged it would start a rodeo party. Could not see the elev trim trying to correct it, probably because the porpoising is so abrupt it does not calculate a correction.