I'm not sure what the problem could be, but when it is cold outside, my tach will jump all over the place. It is enough bouncing to actually go up to the redline and sound the buzzer. It stops after a while once the car warms up.

It seems to be just the dash tach that is doing it, as I see nothing happening on the laptop.


In addition to this, while it is bouncing around, the needle will jump in time to the turn signal if I use it.

Would this be ground related? If so, how can I go about rectifying it? As far as I know, the car is grounded just fine. If it isn't ground related, what might it be?