Saturn - High RPM while idling


I have a 1997 Saturn SL2. At least a few times per week, the engine runs at a high RPM while idling (e.g., 2-3k).

In terms of trying to detect a pattern, it seems to happen most often in the morning when I first start it up, or if I only do local driving. It seems to happen a lot less or not at all, if I do freeway driving for any extended period of time (e.g., 15 minutes to an hour).

Any idea on what might be causing the problem? Do you think it’s going to cost a small fortune to fix? Thanks!

First, if your model has one, replace PCV valve to correct any vacuum problems. If that’s not the cure, clean the throttle body and IAC according to an automotive manual which you can buy any parts supply or borrow from you library. Those are the cheap fixes. If that doesn’t do it, your ECT sensor is telling the computer to mix a higher than normal air/fuel ratio and needs to be replaced.

Thanks for the suggestion. I don’t know what a PCV valve is, but I’m assuming if I take it to my mechanic, he’ll be able to replace it and “clean the throttle body and IAC.”

This is a common problem for Saturn’s, the intake manifold gasket fails around the #1 cylinder. Its easy to check, you should notice that the idle isn’t quite as smooth as it should be. Take a can of carb cleaner, fuel injector cleaner, wd-40 or something like any of those and spray around the intake manifold gasket at the #1 cylinder. If the idle changes in any way, the gasket is leaking.

If you get a check engine light, it will probably be code P0507. The printout will recommend a new IAC (idle air control) but it will be the intake manifold gasket causing the problem.

BTW about $200

Thanks very much for these additional details and the price estimate!