Getting vibration in my seat when in Drive gear and stopped at red light. (2014 sonic with 59K kilometers)

What would be the most common cause? or is this normal for these engines?

Is this a new vehicle for you? Motor mounts?

Yes this is the new vehicle. Is there a way to check motor mounts without taking them off the car(visually) . I was thinking of cleaning the throttle body first and see if it makes a difference..it has 58,000 km (is this the right time to do the cleaning or is it too early for the milage it has ?)

If you shift to Neutral, does the vibration change?

It does improve somewhat when I put into neutral. Also when I start it up in the morning in park the vibration is present.

I'm going to guess that this is normal.

Could I have a problem with PCV valve. I understand this is common problem in these engines. How can I test this? When I quickly remove dip stick, I hear a "woosh" sound like fast moving air.

When I loosened the oil fill cap, it seems like there is vaccumm which tries to suck the cap in the direction of the engine, when I put cardboard piece there, it seemed to be bouncing

You could try replacing the PCV valve to see if there'* a difference.

I had a heavy duty mechanic (my wife'* coworker'* husband) checked out the car and said that PCV is ok. Also the PCV valve is built into the valve cover so you have to replace the whole valve cover.