2002 Other Suzuki Models Vechile instability

Hi,
Iam facing terrible trouble with my car,at speeds between 20 and 40kmph the front passenger side tends to jump,this dissapears at high speeds.
I have got all four tyre balanced,replaced front two tyres,alignment has been done,shockabsorber has been checked.
I cant understand what the problem is!!
Could you please help me as to what is the reason for vechile jumping at such low speeds and what all parts i need to check??

Thanks...