Hi there. I have a 99 civic lx with 190k miles, d16y7. Recently the engine has gotten pretty noisy. I'm not the savviest with cars, but basically the valve knocking sound that typically resolves when the engine warms up is now constant, even with a warm engine. I have checked the valve lash multiple times now and everything is stock. I am wondering if this is perhaps an oil pump issue and how I might go diagnosing it. I understand it's not the easiest fix, though I have done the timing belt so my be I can handle it. But I wanted to get opinions before I go diving into fixing this. Thanks much in advance.