I have a 2001 Saturn S series. Has 137,000 miles and has been very reliable. Lately it has had an idling problem. The idle varies from 800 to 2500 rpms. It changes all the time. It may start out high, or just change as I drive. I had it in for some work non related, I mentioned the problem, and they cleaned out the throttle body. It did not really help. Any ideas?? Sully
Sully,
Is the very high idle (>2000 RPM) usually when you re-start the vehicle after it was recently running and the engine is still warm? Have you noticed a reduction in mileage? Does the engine temperature gauge never go to where it used to when fully warmed? If any of this sounds familiar, then I'd suspect the Coolant Temperature Sensor (CTS).
The CTS reports the engine coolant temperature and the computer enriches the mixture when it is cold. If it enriches the mixture when it is hot (but being reported as cold by the defective CTS), then it runs richer and idles faster.
The part costs about $10 at the local auto parts place and takes all of 5 minutes to install yourself with minimal tools. If this does not fix it, then look for a vacuum leak. Good luck and post what you find for the benefit of others.
Bob
Be examining the pcv line. I'll bet you find it collapsed and/or deteriorated to the point of having a hole in it.
s
If it is idle high, 99% chance it is the CTS.. cheap and easy to change and the result will be instant. At $12 it's a no brainer. Just make sure the engine is cool and you open the collant overfill befor he swap. Swap fast enough and you won't lose any coolant or at least very little. Phil
PCV or EGR. Also possible for a TPS to be bad. Is the check engine light on? See if there are any codes stored and possibly have the OBDII data (not just codes) checked to see if anything looks out of whack. Some of the sensors are cheaper than paying for a diagnosis but sometimes you get lucky other times, the costs just add up throwing random parts at it. I like being able to look at the data stream. It tells you if the engine is running in closed loop (which it should be after it is warmed up and all is functioning within normal parameters). You can read the actual sensor values like the CTS and see if it is giving a believable temperature... Lots of information to be had with the correct tool. I borrow a Snap-On from a mechanic friend's shop.
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