hi,
I have the same prob with my 2wd cossie...I bought a VDO rev counter, plug it as the instructions said....but some times it is good and some times, when i brake or use the indicators or something that use tension, the rev counter begins to become mad.....it revs and stays at high rev !

it is connected directly to the negative of the coil.......!!

also need help.........pleaaaaaaase