LooseBruce

The gauge will go to zero after driving a while and the radiator fan will come on, even though the temp up to that point was fine. this first started happening when it would rain. then it began doing it in dry weather. When it would start working all of a sudden, the temp reading was back right where it should be.
I do not want to burn out the cooling fan by having it run all the time, but I do not what to start throwing random parts at it.

Need4Camaro

iTrader: (1)

I had this problem on my 3.8 V6 Firebird W68 when I owned it. You have a bad thermostat. It is stuck open. Here is exactly what is happening...

The PCM goes into a FAILSAFE mode if it does NOT detect a change in the temperature in aproximately 3 - 5 minutes. If it doesn't detect a change the PCM assumes that something is wrong with the TEMPERATURE SENSOR and automatically kills the temperature sensor circuit (killing your temperature gauge) and throwing the FANS on HIGH INCASE the car is really overheating and getting false temperature readings to prevent itself from overheating...

Whats causing this is a stuck open thermostat doesn't allow the internal temperatures of the engine to heat up SOON enough because coolant is constantly flowing from the block to the radiator and isn't given the chance to heat up. Thus the coolant temperature sensor sees no change in coolant temperature over a prolonged period and throws the PCM into failsafe mode incase the coolant sensor is wrong - to prevent your engine from overheating although it really isnt.

Replace the thermostat, 98% sure this will resolve the issue. If it doesn't... then replace the temperature sensor.

LooseBruce

Thank you. I will give this a shot next weekend!