Autistic Tacometer

[R33S2]

It goes nuts on start up and then settles down to double what it should be reading, then it runs normally with the occasional hiccup, has anybody had this problem and fixed it?

[GTScotT]

Remove the dash and make sure the copper screws at the back of the dash are fastened firm.

They are the instruments earth points.

From there you will need to trace the tach wire for possible breaks or cuts back to its source. Not sure if it would be from sensor to ECU or ECU to tach, you will need to test yourself.