Car running HOT at all times, cools down at idle.
 

My car is running about 260 at highway speeds. When i accelerate it goes up. When I stop at a stop light it goes down. I think its running lean. Would a bad CTS cause this because the connecter on mine is broken off? What would this cause if not?
Thanks for the help

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Jason 89Iroc-Z

That sounds a lot like a missing air-dam, it's the black piece of plastic in front under the radiator. It' very easy to miss if it's not there and your car WILL overheat without it !!

Exactly what my car was doing when on a trip. Turns out I lost my airdam somehow.

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Mark Lock
- 86 IROC-Z - My car, mods and ET's
- -= IROC Online =- - The site dedicated to the IROC-Z

I was having a problem with overheating too. After replacing the water pump, radiator and thermostat with no improvement I replaced the Temperature sending unit to the guage (not the one to the computer) and that fixed it. Turned out it wasn't overheating after all, just a bad sending unit. Don't know if that will help you but I'd replace that first before the expensive stuff.

If your air dam appears to be intack, I would suspect the sending unit at Troy suggests. And not the CTS, but the sensor in the head (between 1 and 3) that send the signal to the temperature guage. These cars have 2 sensors (3 if you count the fan switch sending unit). BTW, if you have electric fans, they SHOULD have come on too if your temperature was at 260*F. Do you know anyone with a scan tool? If you do, then you can confirm what the temperature the CTS (the other sensor) is sending to the ECM. If it is normal, then it would confirm the sending unit for the guage.