I just returned from Rennsport III and had a strange thing happen. I was driving along and suddenly noticed that my tach had started reading about 1000 RPM low at all speeds. The next morning when I started out again it read normal, after about 20 minutes it dropped about 1000 RPM's again and remained reading low the rest of the day. My car has an MSD ignition with the MSD tach adapter. Up until this trip it has always worked fine. Please help! Thanks, Kevin

1965 911