Why is my 2005 vw jetta randomly making a rattling/almost grinding vibrating noise?

And that would do it at random times? It's not all the time that it does it just sometimes but a lot.

I'd check the power steering fluid level. The Jetta can make that strange grinding sound when the fluid in the reservoir is just below the safe level. This is consistent with your hearing the noise when turning or engine at idling speed. Be aware that the system requires Central Hydraulic system fluid; don't just pour generic power steering fluid into the system. If you find that topping it off corrects the noise, it would be prudent to inspect the system for any leaks. Sometimes the line material shrinks and the clamps no longer seal and need tightening or replacement.

mine does a rumbling noise when switching from fast idle to low idle someone help