This started happening today. I have and automatic 2000 honda civic ex with 176k miles on it. When I give it gas, I hear a knocking noise in the engine. I lifted the hood to confirm and the noise is coming from the engine. Under the valve cover. Could it be a lifter? My engine has a slow oil leak from the head. I recently changed the oil and filter this past week. I was having idle issues so I removed the throttle body for a clean hoping it may help, this was a few days ago.. It seemed to help as well as help throttle response. Any idea?

 

Get your valves adjusted.

 

valves normally make a ticking sound

 

"From the engine" is very vague. From the head? From the block? Also, is it a tapping noise, or a knocking noise? Does it vary with RPM, or is it consistant?

Side note: Our engines don't have lifters. Cam touches rocker arm, rocker arm touches valve.

 

It more of a tapping sound. It does vary with rpm. Speeds up the moreni mash the gas.

 

Update. Its the rod bearings. 176k miles on the engine. Its done for.

 

How did you verify that? Metallic fragments in your oil?