I just did my first scan on my 95 LT1 installed in an 86 IROC using freescan.

My MPH readout was 24 when I was actually doing 60.

Is this used by the PCM to alter engine operating parameters? ie for anything else besides speedometer and cruise control used in 4th gens?

Thanks

 

Anybody?? Someone must know this..

 

you can try reprograming it.

 

Yes it is used for fuel trim cells

 

Also used in the IAC routines to adjust idle speed while car is in motion.