Many thanks to lkly2l.
My Speedo is about 5mph fast at 80mph (passing the radar signs on the highway that tell you how fast you are going) and I had thought this meant that the speedo was about to break. 6 months later the speedo worked intermitently for 2 weeks and then quit. Its the only reading on the dash that died.
Like some of the others here i had already pulled apart the dash expecting to find a broken cable leading to the trans, (it has a section for the speedometer cable in teh chiltons book), but alas there was none. Searching online brought me here. lkly2l directions were good on for the speed sensor. its a few inches below the oil filter, verticle mount and about 2" in diameter. I pulled mine out, but in doing so the top cap came off. It appears that the top part (where the electical wires go, its black) fits snuggly into a verticle metal piece that is attached to the transmission. So if you unbolt it you should have 2 pieces (if you pull the black piece out with the wires). I put mine back together and now the speedo works. I think the black piece was not in all the way so it was not making a connection to the spinning wheel inside the speed sensor.