It may be either a faulty gauge or faulty wiring from the sensor to the ECM/PCM control unit, a problem in the control unit or faulty wiring from the control unit to the gauge.
Here's the wiring for the coolant temperature gauge from the 1998-2002 Honda Accord service manual that may help.
Note* The ECM/PCM unit is under the dash behind the steering wheel and not "in" the steering wheel as it might appear to be in the diagram
(click on images to enlarge)
There is no wiring diagram or schematic for the ECM/PCM so hopefully the wire colour of the wire at the sender unit is the same at the control unit connector from the left side engine harness cable.