Or is it my imagination ? My C250d has covered just over 10,000 miles and on the way back from a "sprightly" 150 mile run I'm sure I noticed a slight misfire from the engine , now since then the engine note has gone from a purr to a more growly note on acceleration. I've also notice that the revs will blip up slightly ( 100 rpm) on occasion , when taking my foot off the brake at a standstill. Any views or am I imagining it. Will probably take it in to MB when I can arrange it.