91 Olds Cutlass, won't idle right until warmed up

Also, the Intake Air Temperature sensor (located on your airbox) is another place to consider perhaps. But the coolant temp sensor is a known problem area on those cars, so I would definitely consider it first.

I am wondering more about this temp sensor you mention. Come to think about it, I have seen the fan turn ON a lot. I am wondering, if it thinks the engine is warm and is turning the fan ON. Have you hear of this related to the temp sensor. Could also explain why the vehicle only really runs good when it is warmed up.

My story continues. Still haven't quite understood what is going on. Today, it was much colder in Colorado and my son went to school. We just replaced the themostat, thinking it was causing some of heat problems. Anyway, the car was overheating when it was 10 degrees outside. Sounds like a water pump issue. What does the group think? I would think this could be causing:

- won't idle right when cold

- heater not putting good heat out into the car, even though the system seems to be working

- overheating conditions Interesting, this overheating condition does not persist, seems to go up and down, however, my son has said it seems to be running hotter than normal. The thermostat is rated at 195 and his guage is indicating 220 to 230. Tom

I figured out the problem. Turns out that the radiator fluid was just low. My son told me he kept adding fluid. Small pin whole leak. The fluid being so low must have causing the thermal sensor to get false readings, and the heater not to heat. Possilble air bubble. Anyway, by filling up and finding the leak, problem solved. Now I hope the stop leak stuff works, or we get to replace the radiator.