Just got my first ever Mercedes and I love it. I own a 2004 C270 CDI. One problem I have is that there is a rattling noise (not sure where it's coming from) can be heard in the cockpit. It can only be heard once the engine has warmed up a bit and seems to get faster and louder upon acceleration. It has been on a STAR system at local mercedes specialist and nothing appeared. The mechanic said it might be a dodgy injector but wasn't too sure. It doesn't do it while it's idling or upon first starting the engine. Has anybody else had the same issue or similar please. Thanks