carbon cleaning ba tawag dun? i actually found in the engine bay a tube sticking out of the exhaust system. i think it's where you can stick a hose and let water through and out the back.

anyway, my questions are, how do i proceed? does my engine have to be cold? start the engine first then insert the hose or vice versa? kelangan bang irev or idle lang? they say kasi it would help sa emission test and lessen black smoke.

thanks!