Well, my speedo stopped altogether, so I replaced the speed sensor (no luck), then the speedo itself (three different ones, still nothing). Still have continuity in the wires running from the speed sensor to the dash, but nothing causes the needle to move at all. Does anyone know what I should be looking for as far as either voltage or resistance from the speed sensor? I'd hate to think that I will need to replace the computer.

 

When i had problems with my speedo/tach - it turned out to be the ground on the pass. side of the engine, both units would work erratically and after removing dash entirely as well as removing all of the split loom behind dash and under the hood i started rechecking the ground terminals. What initially looked and felt like a good ground was in fact good insulation with a broken wire inside right at the crimp! Hope this helps

 

Did you line up your speedo gear? It has to be timed right or it won't work.