92 accord while driving or parked the tach needle above 4000rpm will start bouncing like crazy and you will notice the car slightly running different its not a clutch slippage other than that car runs fine does anybody know if the tach runs off of the distribor coil or any ideas would help thanks ray

The tach runs off a pulse from the igniter which is the electronic switch in the distributor which causes the coil to fire. The igniter recieves its pulse from the ECU. So the problem may be the igniter,the tach or the ECU. The cheapest place to start is the igniter, then the tach. A bad igniter could cause the engine to run badly over 4000 rpm. The igniter pulse to the tach also feeds the engine mount control unit, the TCU, AT control unit, and cruise control unit. You might want to see what the cruise control is doing when the tach is jumping around.