Stuck at 3K ~all~ the time? Ignition on or off? If so, either replace it with another or send it to a gauge repair shop. If it is at "0" with iggy off and jumps to 3K with switch on, there's most likely something amiss in the circuit to it.
If you have "watchmaker" hands it's do-able, there are links to a number of good "how to" articles somewhere here in the forum. DKLawson's come to mind.
Sending it to a repair house can be somewhat expensive but the best bet in the long run. We use Nisonger but there are others.
Our go-to guy here is The Autoist, Tony. PM him to see if he may have a replacement to offer.