What are those exactly? I'm hearing a tapping boise from my 99 SE 2.5L with 188k on the clock. How much would replacements be ?This is what I found after tearing down my engine tonight. It had a tick/tap high in the motor after warming up to 210. Other symptoms included a misfire with the tap. This did not throw a CEL. I tried to treat it with motor flush and a couple oil changes. Oh, well. I just wanted to post this in case it helps anyone.