I think it is a manual speedo so take the cable soose at the dash and pull the cable out. Then take it loose at the trans and pull the piece that is broken off out. Go to the parts store and get anew cable and install it with lots of speedo cable lube, If it is electric change the speed sensor.
Last answer is incorrect. If the speedo didn't work then it would have been. The problem is with the cluster. Go to your local salvage yard or eBay and get another speedo.
Getting closer. It is actually the small plastic gear in the odometer. You can get a new one at odometergears.com or get a whole new cluster.
The odometer is separate from the speedometer. The odometer counts how many miles you have driven total, while the speedometer shows how many miles you will travel in an hour if you maintain a given speed. You should immediately take you vehicle to a qualified service technician, and get the odometer fixed.
If the speedometer breaks, it effects the odometer. Check the speedometer cable it may be broken, even under the insulation.
miles - U.S. km - Canada whatever the outer portion of your speedometer shows
My thought would be that your vehicle is originally from a country that uses kilometers. The Speedometer face plate may have been swapped out but the odometer wasn't converted. One mile equals 1.6 kilometers, hence the difference you're recognizing.
Drive on a freeway or highway where there's a speedometer check point. Set your odometer to zero, drive the exact speed limit (try to use cruise control), and after the speedometer check point is over (5 miles), you will be able to determine if your speedometer is working correctly based on the miles driven according to your odometer and the end of the checkpoint.
about 40 miles per gallon
According to a website I was looking at : For a 1995 Ford Crown Victoria , 4.6 : ( 15 city / 23 highway , miles per U.S. gallon )
A Ford Crown Victoria receives an average of 20 miles per gallon: 19 in the city, 21 on the highway.
For a 1998 Ford Crown Victoria : ( 15 city / 22 highway ) miles per U.S. gallon According to a website I was looking at
Sounds like a sensor
The over-all size of the tire and wheel would change the calibration of the speedometer/odometer.
The gas mileage for a 1987 Ford Crown Victoria is 17 miles per gallon on the highway and 11 miles per gallon in the city. The combined mileage is 13 miles per gallon.