I have a 97' Pontiac Firebird that will overheat when the car is at a stop light or when it is running under about 30 mph. The temp gauge will fluctuate from about a quarter all the way into the red and then when i start driving again, it will go decrease severely and then fluctuate as a drive. I'm not sure if it's the PCM or if it could be the radiator needing to be flushed. There are times where the "Check Gauges" light will come on and the car will drive very rough until the fan kicks in then the temp. gauge goes back to "cool" and the car runs find. If someone has an answer please help.

Thanks,
Dominic

 

U might have a stuck thermostat, are U sure the fans are turning on? Are u showing signs of coolant loss? Do you always have to add coolant?

 

Blowed headgasket..

 

I had a similar experience when one of my fans sucked a plastic bread sack up and burned out the motor. You really need to start with the basics:
Do the fans turn on when they should - if not, find out why
Is the system full of fluid - if not, find out why
Is the thermostat opening when it should - ""
Is the gauge reading correctly - ""

I suggest that you not take a blanket statement as fact, and start from the beginning. Are the fans turning on when they should. Is the radiator full. Is the thermostat operating correctly. Etc.

 

fist an over heating problem is some thing you should not let go for to long time some thing could turn in to a big eng problems.
Fist do you have a leak and the coolant is wear it should be,do the fan or fans come on .does the car have a/c if does throw it on and see if fans come on this will tell you if fan or fans are ok and working,if do then may have sender trouble if fans dont come on with a/c off and eng is getting hot and fan or fans dont come on. , let eng get hot and make sure that hoses are all hot if one is cold ,may have thermostat problem or water pump is not working ,how many miles on eng.do you have heat in car and does the belt make noise when stepping on gas.
start with thermostat

 

V6, V8? What? One person mentions the belt (like for belt driven water pump). An LT1 does not use a belt to drive the water pump. If you want good answers, you need to provide good information.

 

I'm having the same issue on a 97 FB. 3.8 V6
The engine was rebuilt a year ago, and has run fine until a week ago. The temperature gauge has started acting strange. The above mentioned issues have been ruled out - no coolant loss, fans operate as they should, hoses are under pressure and hot. For all intents and purposes - it's not overheating, but the gauge says it is, and the PCM responds by shutting the car down. I replaced the Coolant temp sensor, but it is still exhibiting the same behavior.

Any ideas?

 

I'm having the same problem

 

Year and engine in your car?