I here a little "valve clatter" at idle to 2,000rpms....sounds like my old Acura after some oil sludge build up. It does bother me a bit but then again the CF is way more mechanical feeling than my previous cars. The japanese cars I've owned were all sewing machine smooth and slick and even the Volvo C70 was more refined if alittle lumpy with the 5cyl engine.
I just chalked it up to the car being abit old tech.
Still I love it.
Dallas