To be honest I didn’t know where my knock sensors were and I still don’t. When this code popped up in the system I knew it wasnt going to be a cheap fix. After talking around I had people tell me to run higher octane gas for awhile while. Sometimes rarely using injection cleaners will losing up big chunks, doing more bad than good. Either use them often or don’t use them at all. Another idea brought today was checking the air intake. Making sure there were no leaks. Come to find out One of the rubber seals was loose and air was being sucked in the top. Once repositioned and back in place the check engine light had turned off )) btw average shop price to replace knock sensors $720-$900. Parts run about $260. Labor $500