Its not easy to describe. Yes you can feel it at 30 mph in neutral. Although it stops just below 30. Its as if the road is constantly uneven, but the uneveness is too small to count as a bump. As if there are a lot of very small rumble strips on the road at irregular intervals. Its also very similar (from the point of view of how it feels from the seat) when I had a slight misfire, but then it depended more on load and engine speed whereas this feels more dependendant on road speed. You can feel it partly through the steering wheel, though not as much as an out of balance wheel. You feel it mainly through the seat. A friend recently commented on "the wobble" felt in the back seat, so its not just coming through the steering.