Ok, this has been an on-going issue in my '94 V6 XLE and it's driving me batty. Been happening for at least 6 months.

The temperature gauge reads way hotter than the engine actually is. When I start the car, it climbs to the midpoint within 30 seconds, and after about five minutes when it reaches operating temperature, it is closer to the 3/4 mark or the red line. (Lately, it's been creeping higher and higher.)

I've replaced the temperature sender to the gauge and the sender to the ECU. Replaced the radiator. My mechanic verified with his infrared temperature gun that it is not actually overheating.

Could this be a slowly deteriorating gauge? The rest of the instrument cluster works perfectly.

It's important to know that I was pulling a code P0115 (engine coolant temperature circuit) before I replaced the ECT sensor. I reset the code and it hasn't reappeared.

Help!

 

can't help with diagnosis. You've done a good job, imo.
Black electrical tape applied over the problematic gauge should help with you're being driven batty issue ...