Actually, i'm not a New member here. I think, I registered back in around 2006.
For some unknown reasons, the Forum no longer remembered my old email address.

I admit it, i had not been that active when I first was a member to this useful site
due to the fact that one of my kids has had the car almost entire time so
there have been some essential regular maintenance what were undone as they
were supposed to. Long story short, I got the car back late this Feb 2018
with a check engine light on....(nightmare).

Common failed part on this model (2008 C300 Sport) Intake Manifold...(I dislike that word)
Broken components on it were 2 of the actuator arms and the lever and who knows
the interior condition of it. So initially, $600 had to be spent on the intake itself.
Plus $300 on the labor also the Thermostat was also malfunctioned and I told him
to go ahead replace the Serpentine belt while he's at it with no extra cost.
After all that were Done, the CEL is still on. So 2 more crucial parts
have also been replaced (the Map and Air Cleaner Box) because
the car was making this whistling or rather a high pitch sound prior to
the last 2 parts. 3 stressful weeks went by driving with the CEL on.

Took it to O'reilley's ....codes were P0170 and P0173. After a thorough
online research I have made a gutsy move by replacing a New Maf Sensor
just a few days ago but the dreadful CEL remains but something
worth noticing was that the idle is much more stable...
about .700 at park and .600 at the light (Wife has been
driving the car to work through out.

At this point, $1500 has been wiped with not much progress.
As of today, codes came back with same P0170 and P0173
Fuel Trim Bank 1 and Bank 2.....so stressful, please help
share your similar problems past experiences, thank you much.