I have a 2012 G37x sedan and I feel some vibration when I sit at idle. It is not real bad , but noticeable. Is this normal? Thanks

 

Honestly with just your description over the web, it's really hard to say.

Could be anything from dirty throttle bodies, to a vacuum leak, to exhaust components causing vibration, to motor mounts, etc... so many things can cause a vibration at idle. not sure how much better you can describe your issue over the internet without actually seeing the car in person though.