My Rev Counter Is Pi$$ed

Can anyone help my bloody rev counter is driving me round the friggin twist Its constantly bouncing up and down it won't go as high as the engine is actualy reving. If you rev my landys conkers off the rev counter hovers around the 2 and half to 3 on the rev counter.
Can anyone help with info on where to look to find the problem.

Easy one, the rev-counter picks up it's info from the alternator so check the connection there, it might be a single wire or part of a multi-plug depends on the alternator u have fitted.

Thanks Mate i will look into that i thought it would be picked up of the alternator. You just confirmed it for me Thanx.

or make sure ya belt aint slipping

Chuffin' 'eck! My Disco 300Tdi had same problem. Removed and refitted white wire with grey trace several times to remove the corrosion (open circuit) and what do you know it works fine now. Was worried I might have to replace the tachometer ouch £$£$£$$

Big to first member who posted