93 Lesabre Thermostat - Temp Gauge

I have a 93 Lesabre with 128K miles and a dashboard temp gauge.

According to my factory service manual the thermostat should be rated at 195 degrees F. Now my dashboard temperature gauge reads 160 degrees when the outdoor temperature is in the 90s and 140 degrees when the outdoor temperature is in the 70s.

Is this anything to worry about? Is the gauge wrong or could the thermostat be bad? The car is running great although I would like to see more MPG than I currently get in mixed city and freeway driving (18 - 19MPG).

Thanks.

It certainly sounds like the thermostat is stuck open, or you temperature sensor is failing. :screwy:

Pull the thermostat out while the engine is cold, (before you start it) and see it is open. If it is open when cold, replace it. If it is closed, put it in a pan of warm water along with a thermometer. While on a stove, bring the water temperature up to the thermostat rating, to see if it opens all the way. Actually, the opening should be progressive from about 170-195 deg.
If all that checks out, replace the sensor.:iceslolan