Hello! I’ve been seeing my C250 TD for about two months now and two weeks ago I noticed a strange phenomenon: if I walk off the gas at about 3000 rpm, the machine “grunts” for a short time, that sounds almost like rattled tin cans. The stronger I step on the gas before, the worse the noise. It seems to come from the right back side of the engine – but in idle it is hardly audible and with open hood you can hear nothing more except the machine, so that I have the cause no – the turbo is probably not: when I step on the gas in other speed ranges, the turbo turns properly high and whistles without any side noise. – the control chain tensioner will probably not be, because the sound would sound different, would also occur at other speeds and also not seem to come from the front of the engine. My guess so far: the valve of the exhaust gas recirculation. If I go abruptly from the gas, the Masc sucks Is there still good air, but has fewer exhaust gases, so that changed pressure conditions prevail with the ARF and the (perhaps defective) valve clatters. Does anyone have experiences or tips for me or can I help you with anything else? Thomas