C230K stutter at constant speed
 

Hi Guys,
my 2003 C230K (70K miles) has got a sawing idle and mild stutter (not misfire) at constant speed issue.
Gets better immediately with more gas and is also better when hot (ambient and/or engine).

Had the recall for the vacuum hoses on the air box done w/o improvement.
Tried the CRC Air-Mass-Flow cleaner also w/o improvement.
(Got a replacement cylinder head to fix the carbon buildup issue on the exhaust valves years ago already).

Could this be an electronic issue: AMF, temp sensor, throttle body, crank- or cam-shaft sensor, ignition coils etc.?
Also even though its dealer serviced, I'm apparently still on my first set of sparkplugs and fuel filter.

Does anybody have experience with these symptoms and proposed fixes on a 230K?

The spark plugs are only good for 60K on the kompressor 4 cylinder cars.
Of course start there.

If you see no improvement then the mass air flow sensor is the most common issue.