E70 smooth running controller

[mxxxs]

Hi,
I have a ‘08 E70 3.0 sd.
Some time ago, I felt that the engine was running a little rough on idle speed in the morning for a few seconds and after a test with Ista D i got a smooth running controller error.
After testing the values, the cyl 2 was at about 5, over the limit.
I replaced the injector with a new one, but i still get the same error.
I measured the injector rates for about 20 minutes, and the values were above the limit only while the engine was on idle, and only when it was cold.
After 8-10 minutes of driving, all the values were normal.
Dies anyone know what might be the problem?

Thanks in advance
manos