Twitchy rev counter

[millworm]

As above it starts to twitch at about 3-4k, anyone know what it could be before I tear into it

[BRoadGhost]

I had this on an aftermarket tach and my understanding of it is the coil negative needs a resistor in line just before the rev counter.

Don't ignore the issue as it will break your counter in time.

[millworm]

Cheers, will get on it