Speedometer Problem

I have an intermitant speedometer problem. I have pulled the dash and checked all connections. My speedometer continues to sometimes not work. What else could possibly cause this problem?

Let me also say that this is a 1995 Dodge Neon. If anyone has any suggestions they would be appreciated.

When you say does not work, what exactly is or is not happening?  Dose it suddenly go to zero and stay there?  Does it swing up and down?  Is there any noise?

From this wiring diagram: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152800793b2 Click on Fig. 3, it looks like the signal comes from the vehicle speed sensor (vss), and splits to the engine computer and to the speedometer on the white/orange wires.
Check each with a digital multimeter from the vss to the instrument cluster. Check the other leg from the vss to the engine computer. There is probably a 5 volt dc bias voltage. With the multimeter probe clamped to the white/orange wire at the instrument, shake and tug on the wiring back towards the vss.

It goes to zero and stays there. There is no noise. Sometimes it fluctuates back and forth and then returns to zero. Sometimes I hit a bump and it moves then returns to zero.

Check the vehicle speed sensor, which is attached to the transmission. Also look for loose or damaged wiring connections between the VSS and the instrument cluster.