[Ram]

There are always more vibrations at low idling rpm. The less the no of cylinders, the more the vibration.

e.g. A 3-cylinder Maruti Alto has 3 power strokes every 2 revolutions. When it idles at 900 rpm (15) rev/sec, there is a 22.5 Hz vibration -- easy to feel.

By contrast a V8 idling at 900 rpm would have a 60 Hz vibration, more of a low smooth audio hum -- A B1 note (15th key on a piano).

Diesel engines vibrate more (esp. when cold) because of the loose piston to cylinder tolerances, creating piston slap. So a 3-cylinder diesel Hyundai Accent Viva would vibrate more than a Maruti 800.

Engine and gearbox mounts absorb some of this vibration. In older cars with worn mounts, the vibrating gearbox will cause vibration of the gear lever.

This is from the driving end. Another source of vibration is from the driven end : clutch-judder. That can vibrate the whole powertrain and show up as a vibrating gear lever too.