I have a code of p0300 and P0405 on 06 equinox.

You're asking for a best guess, that won't help! .. NO ONE can determine the culprit without first diagnosis and testing .. That requires a high dollar professional quality scanner and the knowledge to use it . Code readers ain't going to help .. I wish it were simpler but unfortunately that's just the way it is. https://repairpal.com/repair-shops