I have a 2003 Dodge Neon, with OBD-II codes:300 and 303, what do they mean and what do i do to fix them?

I have an 03' Dodge Neon. Everytime I cut it on and start to move it, it starts sputtering and sometimes if I don't give it enough gas right away, it shuts off. Also my engine light will come on for a while then go off. My buddy has an OBD-II and he attached to my car. The codes that came back were 300 & 303. I want to know what these codes mean and how do i fix them and the sputtering. If you can help me out that would be a great help.