Well that sucks. I was hoping that a cluster with a tach would just plug up and the computer would recognize it and it would work. Oh well, probably could'nt buy a brand new cluster anyways. As for the temp. guage, I know it has to be the cluster, becuase I changed the sending unit and it still fluctauted, but not as bad. It would go from just below 210 (normal) to the mark in between 210 and 260. I changed the water pump, changed the sending unit, and the thermostat before I found out it was the guage. Got a manual temp gauge in it right now and it never goes above 190, but if I hook the sending unit up, then like I said before, the guage goes from normal range to about 240. Thats why I just wanted to get a cluster with a tach, but sounds like that is gonna be more trouble then its worth.