I had this exact same problem in my 96LX, it worked intermittently for about 3 months before finally dying.

I had it at the dealer for something else and they took a look at it. Apparrently it is common for the damn speedo itself to go bad in the 94-97s

I think the part from honda was about $150 and another $150 to put it in, so I went to the junkyard and got a dash from a 97 Acura CL(4cyl) and swapped in the speedo and tach from it. Cost me $60 at the junk yard and the gauge faces from the CL are so much nicer to look at.

If you want to verify if it is the VSS or the speedo, u can hookup a ODB tool and watch the speed when you drive down the road. There is an off chance that it could be a broken wire, but not likely.