yes trademark na yata ng 4ja-1 yan but i noticed na during cold starts lang may white smoke but pag mainit na wala siya.
minsan kasi once pinagalaw lalo pa nagkakaproblema. linisan mo rin ang exhaust system at least once a month. lagyan mo ng dishwashing liquid (mga 10ml) yung tip ng garden hose to be use then insert mo sa tail pipe, open the faucet till mag overflow then rev it up to 2500 to 3000 rpm then repeat it for another 2 or 3 times WITHOUT DISHWASHING LIQUID para mabanlawan.
you will notice walang usok yan. even emission testing center magugulat
