The speedometer on my '94 Suzuki Sidekick wavers sometimes. This seem to happen only when I'm accelerating in about the 40-60 kph range. I think it may happen consistently under those circumstances; at least, I've not noticed that it wasn't wavering. When it's wavering, it does so in a range of about 6-10 kph, at a frequency of probably 2-4 times a second. The frequency and range seem to be pretty constant, I'm just not real sure what they are.
Is this likely to be a symptom of a serious problem? I have no idea how long the speedometer's been doing this.