Q: getting P1028 & P2006 for 2008 MB C300 but 1.dont feel any loss of power 2.Idle is Not Poor (no)fluctuation

Code P1028 indicates the engine control unit is detecting that the coolant temperature is lower than the thermostat is designed for. This typically can be caused by a thermostat that is stuck open. The thermostat is designed to allow the engine to reach operating temperature before it opens and allows the coolant to flow from the engine to the radiator to be cooled. A thermostat that is stuck open will allow the coolant to flow immediately on start up and be cooled immediately. This can cause the engine to take much longer to warm up or never reach it’s correct operating temperature. While a faulty coolant temperature sensor is also a possibility, the thermostat is the most likely culprit. Code P2006 - Tumble Flap ’Intake manifold’ : Open circuit of sensor lines / Tumble flap shafts stick in the non-actuated position. The flap inside the intake manifold changes position with engine load to affect the air flow. This makes for good power across the rpm range. The actuator rods can break or get stuck due to carbon build-up in the intake manifold. Individual parts for the flap system are not available separately and correcting the problem usually requires replacing the intake manifold as a unit. You can attempt to have an intake system cleaning performed then clear the codes. If sticking due to carbon build-up was the cause, this may remedy it. If the code remains or returns, replacing the manifold is the answer.