The speedometer needle on my Opel Corsa most of the time lies at the top of the scale (200) and doesn't move during driving. Sometimes, however, the needle rests at a different number, such as 140km/h and shows the speed accurately when driving, only with an offset of 140km/h in that case. Over the next days the baseline speed decreases, until it shows 0km/h when standing and shows the correct speed whole driving. The following days, the needle is back to 200 and doesn't move whole driving.
From what I read, the problem could be a fuse for example. It looks to me as if simple the needle isn't fixed properly to the axle in the dial and only sometimes grips and shows the speed. How can I fix this?