Okay, so I just recently (a week ago) had a wheel bearing and a tie rod fixed on my 2002 Oldsmobile Alero. Now, when I press my gas pedal in it's making a loud sound that sound the same as if you didn't have a muffler and a hissing/whistling sound. I looked under the hood and reved it from there and it's definitely coming from the engine. I've had nothing but issues with this car so if someone could please help me or give me an idea of what it could be it would be appreciated!

 

Sounds like an exhaust leak to me? Check the connection on exhaust manifold where it meets the exhaust pipe.