Originally Posted by 99_GRUMPY_GT
And most inportantly do not forget the grounding areas, look them over, see if the grounding pints are loose.
Look around the battery and radiator support etc for grounds and make sure they are tight. If any look corroded, take the bolt out, clean up the surface and tighten down again.
The cluster resetting, the gauges going all the way up and then back to normal, means it has at some point lost primary power. Last time I had this it was what seemed to be a tight connection at the battery post but was actually slightly loose.
Start there and work your way back to the junction box. Also make sure all fuses are seated tightly.