This thread isn't really about a Fox, but I'm betting that the 79-86 crowd has the possibility of the same issues. Instead of typing everything out again, I'm going to attach a link to my post in the II forums. Feel free to post your reply in either forum if you have an idea! Thanks!!
http://www.stangnet.com/mustang-forums/threads/msd-tach-adapter-8920-and-the-stock-tach.890974/
http://www.stangnet.com/mustang-forums/threads/msd-tach-adapter-8920-and-the-stock-tach.890974/
