About a week ago I did the seafoam procedure where you unhook the vacuum hose and feed the engine 1/3 a bottle of seafoam. A couple of days ago I got the check engine soon light and it was a p0300 random cylinder missfire and a knock sensor code. I read it could be related to the vacuum hose so I checked it and it seems fine. I erased the codes and it was fi e for a day until I got the p0300 code again today of the ride home. Any idea what could be causing it?