Speedo Cable Help~~~

[KC_JoNeS]

Yeah, Im new to posting here.  But figured this would be the best place to get my troubles figured out.  I am about to run a second case with an adapter on my 92 22RE.  It is a W56 case (obviously) and the speedo is acting funny.  Most of the time, it works without any hangups.  

But sometimes, maybe colder weather or something, The speedo does not respond at all.  There is no obvious noise coming from the speedo when it is working, so I figure it is an electrical problem as the speed sensor is electronic.  What would be a likely cause for this to happen randomly?  

[CruzrDave]

IF you Check engine light comes on when it does'nt work then its for sure the VSS. If not then I'm not real sure. Have you checked the plug, make sure its not dirty or wires that are damaged?