Problems with revcounter on 1.3s

[CorsaNova]

My revcounter has started to spin like he** up and down when I drive.

When I stand still with the engine running, the revcounter stays in "correct" position.

Anynoe know what this is???

Is it my coil that starts to slowly die? <-cause this is where it's connected, or is it at the gearbox?

By the way, what may indicate that the coil is partly broken?..

[Philsutton]

i'd check that there isnt a loose connection first, could be the wire is about to die or is earthing out some where, its the green wire that goes to the coil by the way.

[CorsaNova]

have just checked the cables at the coil..they seem ok!

But were does my revcounter end up in the engine bay???

[DIY*VALVER84]

the only dash instrument that has anything to do with the gearbox is the speedo not the rev counter. double check your green wire to coil because it sounds like its earthing somewhere hence the up down effect on the rev gauge.