Engine misfires

My niece bought a 2014 spark over a year ago, she's brought it to me for several minor problems that I took care of. Now it had a p0301 code and p219a code. I changed spark plugs, cleaned mass air flow sensor,(which looked pristine) and made sure I installed the coil packs in different cylinders. Now it is throwing a p0300 code which leads me to believe it is a coil pack, I'm waiting to see if it narrows the code down to one cylinder. Has anyone else had this problem? And what corrected it