Your engine in the C280 uses a variant of the 'fly by wire' setup. It does use a cable, but the throttle is all computer controlled.
That aside, I have heard these pop from time to time. Every one was a result of a lean pop. This is a term that is used widely in the industry.
You can have a lean pop from many different causes. One is if the adaptation is going out from an air leak or from the mass air meter being weak. The best way to check is have the fuel system checked for the adaptation. If it is above 1.1, the engine is running on the lean side.
One other thing to check is fuel pressure and delivery. I have replaced a hadfull of fuel pumps on C's.
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MERCEDES SPECIALIST 11 YRS