Temp gauge

Could be faulty sensor, faulty thermostat, could also be resistance in the circuit. If there is no similarity of circumstance to when it gets hot(say after pulling hills, idling in traffic) then I would suspect gauge sensor or thermostat issue. The placement of the sensor is in a crossover at the rear of the engine under the intake. This crossover is maounted to each head with a banjo type bolt the flows liquid through it. The seals that are used, are a rubber impregnated metal washer. I have seen the torque of the banjo bolts(or inadequate torque) cause poor continuity from this crossover to the engine block, resulting it high resistance in the circuit, due to the ground path going through the rubber rather than the metal. Since the system operates on temperature vs. Resistance principle, the extra/variable resistance may cause erroneous readings at the gauge. The dealer sells a crossover kit, that may be the only way the sensor is available.