Hi,
Sorry to hear about your issue. Is this a Premium Model GT?
1) Did this issue present acutely one day, or seem unusual over a longer time period?
2) Does the T.Gauge ramp up at normal speed when warming up & stay consistent while Driving- only not in the typical sweep area?
3) Does the T.Gauge drop to Cold with Key removed, sweep into midrange with Key in Engine Off, or only sweep into midrange when the engine is started/running?
-> Each individual gauge on the cluster is run by a stepper motor, if the below are correct the gauge itself is the likely culprit..
- Coolant is topped off, coolant System not recently flushed, no potential for being air bound, CPU not recently reflashed, and..
1) The motor is running within normal operating temperatures, cold start to full operating temp, verified via IR Thermometer.
2) No CEL’s present & no codes within, engine temp is correct viewed with a Scantool .
3) Motor is not running rich or pinging under acceleration, using excess fuel.
4) The Cooling fan(s) kick on..
5) No overheating issues, recently.
-> If it is the Gauge, it’s not difficult to replace the Stepper motor if you’re comfortable with a small Soldering/Desoldering process. It may also be sent out for repair at a few reputable sites for about 125-150$.
-> May replace the entire Cluster from out of a wreck for low cost.
-> The Vehicle can be driven with the cluster removed while repairs are made.
Once the questions are answered, it’ll be easier to determine cause & next logical step.
-John