Mercedes benz c270 2,7 cdi engine idle

[martinmb12]

Hello! Has anyone experienced a situation with an MB c270 with a 2.7-liter engine where, upon starting, it idles at 1100 RPM, but once it warms up, it drops to 900 RPM at idle? However, if I gently tap the gas pedal when it's warm, the idle settles at 700-750 RPM, and the engine smooths out. But, if I start driving the car again (without pressing the gas, just the clutch), it goes back to a 900 RPM idle, affecting all gears. This means that in 4th gear, the car goes at 50 km/h at idle. I have a new MAF sensor and a new air temperature sensor, and the values are good for all sensors, with no error codes. The gas pedal is also in perfect condition. Please help, as this issue is driving me crazy.