Hello people I've got a problem with my rev counter I've had the problem since I built my car just never got around to sorting it, the ptoblem I have is that on tick over it shows that its sitting at about 1600 rpm when it clearly isnt then when you drive it the needle shoots off the rev counter way past 7000 rpm when it clearly isnt revving that high.
Do any of you have a idea of what it could be?

cheers