Thanks for that, my Mk1 is long gone BUT my Mk3, the current beauty, has a wobbly rev counter now .... sometimes it works fine, other days it's haywire ............ my indy tells me that the unit needs replacing, the bouncyness is caused by old age affecting the solder ? joints in the gubbins of the unit and on a hot day it might work fine but on a cold day the bits inside ( whatever they are ) are a little too far apart to function as it might when 23 years younger.
You must know the feeling, not everything works as it might have in times past . old age you know.
Replacement unit from Lexus is approaching some £3000 they tell me .... a Mk3 secondhand unit might work ok for now BUT for the future, well who knows.
I can live with it and it's idiosyncracies
Malc