Noticed my CLK was idling a bit quickly on the first start today - around 1300rpm. After about 30secs it dipped down to a more normal fast idle of around the 1000rpm mark. Other than this car is running fine, MPG good and no other symptoms. Once warmed up settled to the usual sub 700 rpm. Any ideas on what the correct fast idle should be? Is this the first signs of any particular sensor or component going awry? Will keep an eye out to see if this occurs regularly. Thanks chaps.