Check engine light

I have a 2012 vw cc. My check engine light came
on and then went off the next day then came back
on a few hours later and started blinking. I brought
my car to my mechanic and changed my coil pack
and spark plugs it was giving me cylinder misfires.
It’s been about three weeks since i replaces them
and now my check engine light comes on
randomly will stay on for alittle then go off. Or it will
start blinking and then goes off right after. I’m
getting codes p0301 p0302 p0300. I Have 75000
miles on the car