I think I have the same problem. As I was reading thru the old posts. When my engine is warmed up, when I drive it is fine but when I get to a stop or a signal light, my RPM is at about 400 something like that. And you can feel a little vibration. I tried holding brake with one foot and giving it a little gas with the other just to 500 RPM and the small vibration goes away, untill I release the gas. Then it does the same thing. But when it is cold it idles on PARK at 1500 or so. So if any one knows how to fix this low RPM problem please let me know.

When it is low like 400 I release the brake pedal and it barely wants to move without me pressing the accelerator. That is why it bothers me.
Any help will be appreciated.