Has anyone else experience the needle on the tach bouncing or just not reading correctly?
Since new the tach would occasionally read incorrect, but never a case that could be duplicated for the dealer. Well, now when cold, the tach won't go over 2800 rpm and then "resets" down to zero and then functions from o-2800. After driving on the freeway for a while, I'm sometimes able to press the clutch while coasting and after about 10-20 seconds it will reset to the correct idle (about 8-900) and then it works fine. Otherwise, when I get off the fwy it will reset while waiting at the signal or stop sign.
I took it in for service and was told because I have a colored guage face overlay they won't even look at it. I didn't remove the needle. I only unplugged the connector and opened the plastic cover to slide the new face in. Now they are having another service rep call me. (to avoid pulling the needle and really having problems I made a cut from the center to the outside edge right under the needle when pointing to zero)

 

I dunno. Maybe the base of the needle (where it's attached to the pin) is rubbing the cutout of the aftermarket face? I've driven my car when it was FREEZING, barely 20 degrees, and the thing never did that.

 

I second this, I haven't seen such an issue. But I have seen speedos go bad before and it's possible that your tach needs replacement, but if the dealer can't duplicate the concern, they can't do anything about it. You may have to leave it overnight and let it get cold.