Why does my brand new 2014 honda civic vibrate when put in reverse ONLY when engine is cold?

I have gone to honda many times and they keep telling me the car is completely normal and nothing is wrong with it. The car vibrates a lot ONLY when the engine is cold and I shift gears, mainly into reverse backing out in the morning. It will stop after a couple minutes and the low temperature indicator is gone, but I have never driven a car that vibrates like this. Every car i've driven especially when its below freezing doesn't vibrate at all. So again, only vibrates when engine cold, worst when put in reverse or when i stop at a red light. Please help me, honda keeps dismissing this and to me it worries me.

Take it to another Honda dealership.

That is not normal. They just don't want to deal with it while it's under warranty. Tell then to fix it or give you another car. And don't back down. New cars are covered under Lemon Laws. Know your rights.

Insist that the Honda dealership who keeps dismissing your complaint, keep the car overnight, start it in the morning (preferably with you being present, too) so they can witness for themselves exactly what you're talking about.