...its the EVAP or Knock sensor? I thot it was cos the gas cap wasnt properly replaced when I got some gas, and wanted the mechanic to turn off the check light but he kept insisting he needs to change the knock sensor, pls share your experience if u've had one

Yeah but if there was a code for the knock sensor too what then??? Just drive it if it comes back on then have it scanned at autozone and repost the code.