Speedometer Needle Jumps

1992 Olds 88 with 3.8 engine. The speedometer needle will be fine then it starts to jump around the gauge. Sometimes it will not register at all. After jumping and not registering it will move back into proper position. Car never looses actual speed, just indicator. Car runs fine otherwise, just annoying while trying to stay within sped limit. Can someone shed some light?

Sounds like your speedometer cable is loose. My mother's Escort has the same problem but I dont know exactly how to fix it....

I guess that wasn't much help....