Need something to do to my truck
 

Well I'm running out of things to work on so I've got this problem with my tach. It jumps around all the time maybe 200 to 300 RPM. Its done it since I first hooked it up and it is not constant. I have a MSD 6A box and the tach is on its own circuit. Any ideas on where I should start with this problem. I'm calling MSD this morning to see if they can help thanks for any help. John