Rev counter with a mind of its own.

[wil08]

I have a L reg 306 D Turbo. she a great car but her age is now showing with the Rev counter playing up, it works sometimes but when i say works the arm just moved up and down not according to the actual rev. What is wrong? isn't there a sensor off the flywheel or cable? i dont know ?

[iceman]

there is a crankshaft sensor on the top of the gearbox against the engine.loosen the 10mm bolt and slide out clean the pickup end of the sensor and refit.this has fixed mine