Tachometer was working great.Drove my car(70 Javelin SST 390 4sp.) today with the kids.Coming home noticed tach jump all the way to 8,000rpms while going 40mph. Let the car sit for an hour and started it up.At Idle the tach was reading 4,000 rpms. Also noticed when I turn the power on without starting the car I notice the tach jump a little and set back down to 0.Never have this happen before.Checked all wires under the hood look fine.
Is it shot???? Any suggestions??? Thanks for your time.
Chris