I had the evap sensor code as well. Wen i installd my skunk2 IM in my gsr i had to "T" my PCV with the line the running to "purge" side of the black canister. That cleard that code for me, mayb there are other ways.
As far as the knock sensor it shud sit bhind the block under ur manifold, color is green i believe.
Hope this helps!