About a week ago I noticed a knock at about 3k+RPM. It doesn't seem to be getting worse but my acceleration is garbage some days. No check engine/service engine lights. Has roughly 160k miles but always well maintained minus one time the oil ran quite low from a .

 

Have You figured out what part of the motor the knock is coming from? Valve train or bottom end? Will it make the noise in park or neutral by just reving the motor?