91 XJ 4.0 Temperature Gauge Problem

Once my engine gets to normal running temperature and I go the shift (manual 5-speed) and the RPMs go up (1800 to 2500), the temperature gauge reading will drop. Like from ~190 to ~120. As soon as the RPMs drop back down, the gauge goes back to normal operating temperature. No other gauges behave this way.

Thanks

Truth be told, XJ temp sensors and gauges suck as it is.

Id start by checking the wires to the sensor, replacing it ($3).. ANd if it still does it, wire in an external gauge.

my '88 did that. the temp gauge would fluctuate with rpm; turned out the connecter on the sending unit was loose. gave it a squeeze with some pliers, it was fine after that.

Where is the sending unit for the temp gauge. I see one close to the thermostat housing.

I found the one for the temperature sensor. It's at the rear of the engine. And yes, tighting up the connection there did fix my issue. Thanks for the suggestion.