Hmm... well that didnt work. Did the same thing again today ... switch ignition on, wait for red light to go out and in that time the rev counter trembles at zero (with a rapid clicking noise) the thwacks to full deflection. Switching off and it drops to the red line. Switch back on and it drops to zero. Not every time of course as that would be too easy. Time to get an obd11 reader I think to see if it is a sender?
Incidentally it has always randomly stuck at the idle rpm on switch off, so it's always been a bit badly behaved.
Nick, I'd check all the feeds to it first as it my just be a loose or dirty connection causing high resistance
