I have a 96 accord LX... (276 000 km..sort of)

Yesterday, the speedometer went haywire. It seems to stick on 28 km/h. When
you slow down to stop, it kind of bounces, but doesn't go to 0.When you turn
off the ignition, it goes to 0?? Sometimes, it seems to work fine.. and then
goes haywire again..

Does anyone here know what the cause may be????

BD