Ok I'm an Old School guy.. soooo

[zero cool]

Carbon deposits can cause a rise in compression ratio. That rise in compression ratio will cause detonation if everything else stays the same. Try running some of that cleaner that is supposed to get rid of carbon deposits and see what happens.

Or try stepping up in the octane rating of the gas you use. That would also get rid of your knocking.

[Dusty]

two common things that happen is the mass air meter goes bad and causes a lean run setting in the computer which results in the detonation or the o2 sensors either one goes gunny bag can set off a lean run. many times it wont set a code till its really bad. but pullin gth ecodes is a good idea