Mitsubishi Repair Problems? Ask a Mechanic for Answers ASAP
On this model the output shaft speed sensor is what is used to determine vehicle speed for the speedometer.
It is important to note that you can not use aftermarket input/output speed sensors on this vehicle... they do not get along at all. If you did, you will need to get genuine Mitsubishi sensors from a dealer on there before the readings from either can be trusted.
Do you have access to a live data scan tool to see if the computer is reading the proper vehicle speed to begin with?
If you need further help just let me know.