Since it doesn't happen at larger throttle openings or under any other conditions, you're obviously looking at engine tuning. Remember the S65 doens't have a MAF, so low-rpm fueling is not perfect. When cold, it can buck like a bronco. And when hot, it can be jerky if engine is LUGGED.
I'm sure many of us would experience the same issues, but I never lug my engine like that. I've never experienced any issues at those rpm in 2nd or 3rd, but the rare few times I've accelerated from those rpm when anticipating a light to turn green but another one in front is red (no need to accelerate), I maintain speed at less than 25% throttle until above 2K. If I have to accelerate quicker, I always downshift first.
Bottom line is there's no problem man. Just adjust your driving habits. And your engine will thank you for it
. If you don't like to shift, you should have bought an automatic
. Take care.