Thanks for the help guys! Turns out I was missing the fiber donut that centers the stud. I also was missing the fiber washer. Spoke to Auto Instruments because they rebuilt the tach and he had me just center the stud and use a nylon washer when tightening it down and the grounding appears to be fixed as it no longer does it. Perform graphics sells the kit that includes the fiber donuts, nylon washers, etc for $30 in case anyone needs them. Thanks again guys!