I recently rebuilt my first Duramax engine thanks to the knowledge from everyone here. I got the truck running today it starts great and seems to run fine but I seem to be having an issue with the Rpm gauge one it is started the gauge doesn't move at all if I tap the throttle the gauge will jump and seems to jump to the correct spot im not sure where to start diagnosing this I have also had an issue with a couple of the gauges not working(which happened before the engine was pulled) but if I plug in my scan tool to the obd port all the gauges work and operate as they should.(ground or power issue?)