2014 chevy spark turns over but won't start

What is your question?

Acts like its going to start (sometimes does but misses terrible). I have 57psi fuel pressure. The only code is P0300 and battery is fully charged, with all terminals clean.

What makes this problem better or worse?

Started running rough cut it off and now won't start

How long has your 2014 Chevrolet Spark had this problem?

Just happened