Problem after service.

[Vaszax]

Hi . I am having a C4 Picasso 1.6 HDI ( DV6TED4) and after timing belt and egr replacement iam getting a small hesitation mostly between 1300-1800 revs. The hesitation ( like a slight breaking) comes when i drive in a steady speed and not when acceleration. Does anybody have a clue about that? Could that be due to wrong Egr fitting, or wrong declaring of the new Egr? Thanks in advance!

[Vaszax]

Forgot to tell that there aren't sny lights flashing on the dashboard!