Speedometer Way Off

Nelson Nolte

New Member
Apr 30, 2016
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I just bought a 2004 GT and the speedometer is WAY off. It says 20 mph when I am going closer to 60 mph. When I use a scan tool, the PCM also reports that the car is going 20 mph when I am driving closer to 60 mph, so I don't think it is the speedometer. It must be something with the PCM or the VSS.

The guy who owned the car before me used a tuner that I still have. The tuner is a Bama Performance SF3/X3. I used the tuner to return the tune to stock, but the PCM is still calculating the car speed as way too slow.

Do you think there is something off in the computer or a bad VSS or something else? Any help is appreciated.
 
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