Rattling/vibrating sound

What is your question?

My car makes this rattling/vibrating sound while in drive but idling (stopped at a red light), the sound is coming from the front passenger side. I also noticed that the sound starts when the engine warms up. I had the guys at jiffy check to see if the passenger motor mount was broke but I was told it was not. What else can it be? The sound is driving me crazy!