I noticed that whenever I move in reverse, the car runs like crap. It feels like its going to die, and it makes this horrible sputtering noise. It doesn't go away if I use a lot of gas or use perfect clutch control. No code appears while/after this is happening.

I've also noticed that after doing this a few times, the car had that gasoline/heavy exhaust smell. Not sure if thats related or not.

I am pretty sure though, that this is a result of trying to back up a hill the other day. I was trying to back up and just wasn't giving it enough gas so it stalled a few times.

I've also been getting an intermittent P0203.

Any guidance would be much appreciated.