Probably not the most important issue in life, but something that really ticks me off. Cars come with gauges to indicate speed, distance traveled, fuel level, and engine coolant temperature. I have installed a ScanGaugeII in my car that reads many of these things directly from the car’s computer. The photo below shows the SGII below the instrument cluster. Notice that the car’s temperature gauge indicates the coolant temperature as 175F, which is “normal.” The SGII shows the coolant temperature is actually 216F, which is still within the normal range, but is 41F higher than what I would think it was without the SGII. That’s quite some “measurement error!”