Will a Cracked motor mount cause my civic to shake alittleor something else?

I have a 93 civic and everytime i come to a stop and the engine is idling i fell a shake/vibration thru the car, is this from a cracked motor mounts or something else. I noticed in the winter when i would first start my car up in the morning the vibration would be gone, but slowly would come back as the engine got warmer. Please help...