I'm having a weird problem recently that the tachometer gauge and the voltage gauge stop working for a while; however when i a hit a bump or something they will come back on and then somehow stop working again.
i was thinking whether i have a loose ground wire of these two gauges?
obviously they are somehow connected together since they are the only two gauges acting weird, the rest are fine.
does anyone know how could i fix this problem? thanks.

 

your cause sounds like a good possibility and there's not much you can do except trace the wires.....are these factory gauges...what year and model? That would help me try to find some help in the wiring diagrams....

Mine doesn't have either as a factory mount. My tach is added so it is easy to trace the ground wire.....