Pontiac Repair: temp. gauge, engine temp, engine computer

Question
changed thermostat now temp. gauge reading above 260 when engine is cold on a 2001 grand prix with 3.8

Answer
Hey David:

Did this engine overheat? If so the guage may have pegged and stuck there. Does it run okay? The engine temp sensor for the engine computer is also the same one for the gauge. If it runs okay when it's stone cold then I would venture to say the temp sensor is okay as well. Strictly a guess is the gauge it's self. Good luck :)