Kung timing chain and tensioner, the clatter will come from the right side of the engine during start-up. IF not, check mo rin yung dinescribe ni Yebo... although mababa pa mileage ng car mo para magkandaganyan; di nga masyado naalaga ng previous owner.

Yung MAF sensor is right after the air filter box. Yung may wire na nakakabit. Sensitive part yan so pag nilinis, don't touch the inside of the sensor and just spray the electric contact cleaner into it.