My car hates me like Romney hates Giuliani


So, I have a 2002 Hyundai Accent with 36,000 miles that has taunted me with minor problems since I purchased it. Recently, it began making a low volume, but noticeable ?peddling? sound occasionally during and after I accelerate (think of the sound that comes from a piece of cardboard hitting a fan blade). This sound usually appeared when I took my foot of the gas pedal and the car was going anywhere from 20-40mph. The sound stops once brakes are applied but sometimes begins again when I let go of the brake pedal. While driving on the interstate today, a loud sound occurred almost like something snapped and the ?peddling? sound began at a very loud volume. Obviously, I am not driving the car presently and need to get the car fixed. But, I know not much about cars and need some idea of what has happened so that I can make sure to not get scammed while trying to get this fixed, or better yet, see if this is something I can do myself.

Also, just for reference, the initial peddling sound did not begin until about a month ago when I took the car into the dealership to get a mechanic to determine why it failed the emissions test?.people initially told me the catalytic converter was out, but then the dealership informed me that the gas cap must have been loose prior to me getting the emissions test. The car has subsequently passed the emissions test but now has this glorious issue. Any suggestions are warmly welcomed. Thanks!