There are a couple of possibilities;
The Sebring is notorious for going through motor mounts. They all have to be replaced at once or the ones near failure will cause the new ones to fail.
The car could be mis0-firing.
The crank harmoni damper could need replacement.
Here is a diagnositic walk through of vibrations at idle. It may shed some more light on the subject and explain what you are looking for and what it will take to fix it.
Wednesday, December 7th, 2011 AT 5:21 PM