With no punctuation, I can't tell what you're saying. You drove the car once or the problem occurred once? The problem occurred at 20kph or after you drove for 20km? You gotta clarify "seems to be fin steering isnt affected".
I take "and its while accelerating no bumps can hear clunking knocking sound id say" to mean you hear something on smooth roads and you don't have to travel over bumps. If that sounds right, my first suspect would be outer anti-sway bar links but you typically can't hear them rattle at anything higher than parking lot speeds. They were a real common problem but not a safety hazard. The clue is they would be perfectly quiet in the parking lot if you turned the steering wheel just a little to either side.
Lower ball joints didn't cause a real lot of trouble but they can cause a clunk, usually when cornering or on bumpy roads. If you only hear the noise when accelerating, see if the same noise occurs when standing still in neutral and raising engine speed. If it does, suspect something driven by the serpentine belt. If the car has to be moving, it might be best to have it inspected at a tire and alignment shop. A rubber splash shield could be loose and flapping in the wind. There's also a rubber seal along the front and rear edges of the hood that could be loose.
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Tuesday, January 31st, 2012 AT 5:42 AM