That's good data. The cold to hot ratio is about 3:1, which looks about right for a ratio. On the sensor that I am adapting for the '48, cold is about 100 ohms and 165-degrees is 33 ohms; close to 3:1.

What does the gauge read with the cold sensor connected?

Do you have a new gauge to check things with?

The answer may be a series resistor to cut current back when the sensor is hot.