Sporadic Speedometer

[nsm484]

Well, After Encountering my first major understeer in the SVX
(15mph curve, Light Drizzle, not enough to clean road of oil),
about 5min later, I was holding her nice at 40mph, when all of a sudden out
of the bottom of my eye I see my speedo needle drop to 20, then to 50 and back at 40, and It has happened to my mother a few times when she
has borrowed the car as well. I was wondering, Is this a sign of a bad
Speedometer Sensor.. or more related to the electrical connection between
the Dash and the Sensor.

And no, Not getting any Check Engine light, just the Sporadic Needle jumping,
and its every once in awhile, not all the time, more like 2% of the time.

Any Idea's? Thanks in Advance