I have an 02 L200 eco tech. After the car warms-up, a high pitched noise comes from near the throttle body. I thought at first the alternator was making the noise, but when you turn off the engine, the noise seems to persist for two seconds after the engine has completely stopped. The noise sounds like when you take a bladeof grass between your thumbs and blow across it. I removed the throttle body and cleaned the carbon build-up off, and checked the vacuum lines for cracks and the noise is still the same.https://www.saturnforum.com/smileys/smiley19.gif Any ideas?

Do you know how to check for vacuum leaks?, if so get to checking.

I should have mentioned that the noise only comes out after the car has been driven for a short while. I have sprayed carb cleaner on all the lines and i didnt have the engine bog down or rev up.Are there any noises associated with the idle air control valve, or anything that the eco tech is knownfor?