Hi Rumesh, thanks for the info didnt know it was the IACV, and nop we cleaned it after removing throttle body from manifold + we removed the manifold from the engine to cleat it too. thats how we found out that the line to IACV is blocked (filled with carbon deposit from bottom of the manifold to the valve)
car is running smooth now thanks to this thread and Mr.Dammika Fernando. he did a good job of tuning. he didnt have to remove anything to clean except for spark plugs and the air cleaner to inspect. I never seen a guy equipped with so much of tools and monitoring devices. according to him the valve timing is bit off (retarded) so have to fix that and that explained excess carbon deposit inside inlet manifold.
Thanks for sharing information guys.
for anyone who wish to visit Mr.Dammika he lives in Cotta road, no 129 when you coming from Boralla to Rajagiruya left hand side about 100m before the railway crossing. it is not a garage he does it at his home so dont look for a garage you will never find his place. and better get a appointment in advance he does only one vehicle at a time.