Today as I was dropping my girlfriend off I was merging into traffic and when I hit the gas (almost floored) there was a couple pops from the back right side of the car. It has neve done this before. When I dropped her off I back out of her driveway and when I put it into drive and hit the gas (moderately) it popped again. I can hear and feel it when it does this. What could be wrong.

 

Okay first of all someone has to have an idea, a loose rearend maybe, something broken, I don't know. Anyway it happened again when I left work, and it definetely feels like something is broken and moving around.

Any help would be greatly appreciated.