Mine is facing the same i have done 20000 kms approx, last month got it tuned from suzuki 3s. all other noises have gone and engine has become smooth. but the hesitation on pickup is still there like when u r climbing on bridge in 3rd with ac on and u press accelerator....nothing happens and it doesnt picks speed , sometime it picks up speed very slowly
or while normal driving u press accelerator, car responds very slowly. for this i opened the plastic air flow pipe and inspected the throttle body.... it goes like this.

i bet the sensor behind this are also clogged.....will go to my mechanic and get it serviced.