The mileage gauge on my car recently died, can anyone tell me what the mileage is run off of?

 

If you are talking about the odometer, there is a small gear in the speedo head of 944's that falls apart. Go to rennbay.com to see how to cheaply replace it. Or you'll probably have to send the speedo and instrument cluster to Hollywood Speedometer (find them on google) to repair it. It's not too bad $$ and they're quick turn around.