In 30 years Ive found most coolant sensors go to -40 so the computer thinks the car is super cold and runs rich.Ive replaced hundred and you cant get the info without a scanner.I think I had one in all the years that was showing 260 degrees bad.Now Ive seen bad computers etc show some crazy readings.I had one car that was showing batt voltage at almost 30 volts on the scanner.The charging system itself was only reading 14.2 Volts.Rocky