I was tracking the car and my tach went nuts once the car was warm. It would bounce from 0 rpm to 4000rpm or worse bounce to 8000rpm hitting the buzzer.

What could the cause be? I changed out the coil and that was not it.

This is on my e6K Turbo 10th AE.

Any ideas?

thanks.

 

Have you checked the wiring around the coil plug? Spastic tachs are either a wiring or tach problem usually.