I just purchased a 1985 IROC Z28. The temp gauge is not reading accurately. It will stay between first and second lines. When I turn off the engine and turn on the parking or head lights, it seems to read accurately. Any ideas on what I should look for?

 

I would look for a faulty ground strap to the engine, or else look to see if the connector has degraded at the sensor. The temperature sensor is a thermistor, and if the resistance is wrong due to faulty wiring, it will make the temperature read strangely. If you have to turn off the engine or flip on the headlamps, I am leaning towards a disconnected ground strap somewhere.

 

Thank you, I will look into both of those suggestions and update what I find.