Guys- Need some help/ideas on this knocking/tapping noise coming from my son's corolla. He has the 1zz Fe motor. The car has ~130K miles. Sounds like a valve to me. I have checked the valve clearance and both the intake and exhaust are in spec. Short of pulling the cams and digging deeper, thought I would ask for help. please see video on the link. any help with be much appreciated.