Q50 2.2d engine issues

[Miodrag]

I have been experiencing intermittent engine issue. Few times when engine starts from cold I would experience serious engine power loss that would manifest itself by very sluggish acceleration, and at the same time if automatic gear leaver is moved to manual gear change mode, it would not change gear, including no downshift, but it changes gears in fully automatic mode. Interestingly, once car engine is restarted , problem disappears . Have visited Infiniti couple of times , they have changed boost sensor but problem still persist. Has anyone experienced similar issues?