I'm experiencing some problems on my 2011 Nissan Sentra. Every time I start the engine, I hear a whining noise under the hood. It's not a screeching sound, or a knocking sound, and it's definitely not a rubber to rubber sound. The sound also comes up when I shift to reverse and it goes away after I shift back to drive. It comes and goes, specifically after driving for a while, and attempting to start the car after parking it. There is also a foul smell very similar to gasoline that comes out after driving the car at a constant speed without any stops. I then stop at a traffic light or a stop sign and the smell makes it's way inside. This happens with the AC on or off. Also, the car struggles going up a hill and releases the smell too. Not sure what to do. I apologize for making the question too long, I do appreciate your time with this matter.