yupp.that rite...check for car timing...distributor,fuel regulator etc...mine also knocking last time..but when the mechanic adjust the distributor da krg knocking...my friend bt when use bigger aftermarket jasma extractor knocking happened but when change to standart extractor no knocking anymore...knocking sound me us fell our engine like an old engine....tapi mmg old pun..hahaha..90an maaa