My Yaris 1.5TS Speedometer bouncing.

[icelandictoyota]

I brought Yaris 1.5Ts Manual, with only 80156 miles on it. only 1 older guy who had it since 2001. (new) When driving the speedometer goes up then sometimes back down to zero, back up to 160 km/h (100mph) or higher then back to real speed. If i'm driving on straight road constant speed it will show real speed but when slowing down and accelerating it can go anywhere from 0 to 200 kmh /.  

It's not digital dash just regular needle instrument, Anyone have idea what it could be ? i know the wheel bearings are new in front, 1 brake pad is out of round, so car shakes a little when braking.

[Jonmartin]

It sounds like the speedo I had on my 1964 Mini. Which I had in 1970. It meant then that the cable from the speedo to the gear box was stretched and ready to break or that the gearing in the speedo head was nackered. Usually replacing the cable worked, but sometimes you had to replace both the cable and the speedo. Thought this problem went away with modern cars.