How to make smooth infinite movement of gameobjects having sprites?

Hey, I want to make smooth infinite movement in a 2D game.
Details: I m working on a 2D game in which the sprites are moving downwards. I have used pooling i.e. the last gameobject is changing the position when it is not rendered by the Camera. The issue is that when it changes its position it is not smooth and background seems to be vibrating on movement. I have already tried out Lerp and transform.Translate but the movement is not smooth. Please suggest any other method(s).


It is similar to the gameplay of Piano Tiles.

Please help me out.

THANKS a lot in ADVANCE...

 

Using Unity 4.3? It has some issues look at:

http://forum.unity3d.com/threads/203552-Stuttering-issue-on-Unity-4-2

http://forum.unity3d.com/threads/24...-on-iOS-and-on-other-platforms-works-flawless

 

How strange! I've done something like this recently without problem ( so I don't think there's an engine issue )
Have you got any sample code?, might be able to spot the problem that way.