To Nathan and Lee,
Yall have enough electronic's experimenter knowlege and experience to make a much simpler and more reliable tach in less time than you can fix that factory unit...think about it... a couple of magnets glued somewhere, a sensor, a counter, a clamping device... and a few filters.... yall can do this... since my car does not have a stock tach I will be thrilled when you design one which I can replicate... Radio Shack here we come...