5 October 2018 - sudden shutdown cont'd

Earlier today when I did a drive test, the car stumbled for just a fraction of a second but did not shutdown, and it was electrical not an engine issue.  I found out that although I had disconnected the tach, it still had power to the internal lighting.  When I had previously removed the tach completely from the electrical system I had no issues the entire week until I re-installed it.  So I am now in the process of checking/replacing the wiring from the MSD box to the MSD coil, and from the MSD box to the ignition wire.