Timing chain and chain tensioner need replacement. I replaced my tensioner yesterday and it is not as bad at initial first startup, but mine goes away once warm. If yours is always that way at idle then you need a new chain as yours sounds stretched. Which is common over time. Chains are 50 bucks.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....