1 pointHi- An old saying is - An engine wants what it wants - . Perhaps make it richer in the areas where you feel this noticeable bucking. To me this is a sign of running lean . With your cams you can get intake reversion and all sorts of weird pressure waves happening that can effect smooth running . Especially at that point of light throttle and low/medium engine speed . Dont be stuck on A/F targets at this particular problem area - Try it at 0.9 and see how it runs .
1 pointupdate: my lambda values on the ecu was crap since calibration was wrong. could not find the correct values but we have retuned fuel according to gauge this time. most of the bucking went away and it's better now. so there were wrong afr values in ecu readings. now only in 2nd gear if you force to drive constantly at 2500 rpm there is a little bucking and i guess this is normal?