So my girlfriends mdx has a CEL on and runs a little rough but nothing terribly bad and also sometimes it cranks over but wont start immediately. I scanned the codes tonight and got 8 different codes, p0301, p0302, p0303, p0304, p0305, p0306, p0300 and p0172.

I have been researching the codes and they all seem to be some sort of misfire but Im not sure where to start with trying to fix it. Any suggestions???