RPM's Don't Want to Drop from 3000 when in neutral

Hello,

My 2000 Alero (Stick Shift, GX 2.4L) has an issue. When ever the RPM's get to about 2500 or higher, and I take the vehicle out of gear (either for shifting purposes or to coast in neutral) The RPM's won't drop. Instead they will hover at around 3000. Not very good when driving in town and the motor is racing every time I go to slow down. The way I deal with it right now is to quickly put it in a high gear, so as to knock the revs down, then put it back in the proper gear and proceed. Also to note when idling it is a very low rumbling idle almost sputtering out but not quite.

One more thing, last week I did replace the IAC Valve (with used part not brrand new). This did seem to correct it, when I took it for a test drive immediately after replacing, but a day later the problems started up again.

Thoughts and suggestions appreciated.

Thanks.

I would say you have another faulty IAC valve. Try a new one.

Take a look at this video, it may help steer you in the right direction, or help with troubleshooting!
http://www.youtube.com/watch?v=xBV9BmjFZVs