Originally Posted by 3050rpm
. . maybe it's just a sometimes annoying idiosyncracy, akin to a birthmark.
To the contrary, this is not unusual at all, particularly with the M50 engine. Additionally, earlier versions of VANOS were fairly crude at best. Complaints vary widely, from rough idling, rocking from side to side, to near stalling in some cases. Power and stability at the lower end of the rpm band is not one of the best accolades of the E36/46; they really are much happier at higher revs. Their design is focused on a normal operational range of about 2k - 3.5k, and beyond for full delivery of stated horsepower. The 3 series can easily be not
the most fun car to drive in the city, and it can be a little tougher than the average car to keep it flowing smoothly. And this is something many "3" drivers hate to admit about their car, so you don't hear it too often. But you'll note that its personality abruptly changes once you have some more space and open road- this is the car's hallmark.
In short, don't be afraid to maintain higher revs, and your car will be happier.
Of course, something could really be wrong with the car beyond its design limitations. Maybe check for any vacuum leaks. Or have the dealer check the DME/ECU to see if it's running the most current software upgrade(s). You might also consider getting an aftermarket chip. Aside from increased HP, they also make corrections and adjustments for a smoother response curve.