Loud (Rough-like) sound when accelerate

When I accelerate, even from a dead stop, there is this loud rough-like sound. It sounds like it's coming from the rear right, by the muffler/tailpipe. This did not happen yesterday, just today it started.

I still am able to accelerate but seems like it holds back going up hills.

Muffler? Fuel filter? Spark Plugs? Any of those start this noise this fast? :confused:

Thanks,
Kelly

First of all what year is this car?