Ok my temp gauge started fluxuating and then went out completely. The CEL came on so i went to AutoZone to have them scan it and see whats up. It turns out it was the Coolant Temp. Sensor so i bought it, changed it and now the light is still on. I went back had them reset the computer and about 4 miles down the road the CEL came back on and the gauge didnt work no longer. Can anyone tell me whats goin on!? Help on how to fix this would be awesome too
First make sure the sensor socket isn't corroded to hell. Maybe there is a twichy connection which causes erratic readings when you go over bumps.
I'd try sticking various resistor values into the socket to see if the ECU picks up on it. Even better is using something like a scangauge to see what the ECU thinks the temperature is. If the ECU's reading seems sensible but the gauge is still off, I'd check the instrument panel harness.
2002 Cavalier 2200 5spd