Tach bouncing, not VR or springs?
 

My tach bounces horribly when accelerating and decelerating. This is in my '75 w/ 3.2 and megasquirt. I've datalogged the voltage and there are no spikes. I just tore apart the tach and the springs are intact. Do you think they have weakened?

Are there replacement springs or a way to "dampen" the needle more? I've also had a problem with the tach not working when it's hot out. It will not work at all when first starting but starts to work little by little as I drive.

So what's up with that?