Hi, so I have a 1990 300zx TT and my speedo is stuck at 160mph. I noticed that when I'm going about 70-90mph that it starts to go back up, but it is still on the right side of the speedo. Since it moves at these speeds, I have hope that I could fix it. Am I wrong? Has anyone ever heard of a problem like this before? I havent seen anything anywhere. If I cant fix it should I buy a new cluster or just keep buying old speedos til I find one that still works?

Thanks,
CarKrush