I have had my '91 NX for 4 years now, straight from Japan to New Zealand,and had years of flawless yet economic performance bar one thing. About 6 months ago the tach started flicking erratically and now spends much of its time dead beyond the redline occasionally spurting to life and reading accurately before flicking and stopping again. Has anybody experienced this before? It coincided with a period of rough idle now fixed by MAF regrounding(thanks SR20DE ring). I'm hesitant to remove the dash and at a loss for pointers(no manual). Is the sensor off the coil?