Throttle body slow reaponse

I removed my air intake pipe to check the functioning
of throttle body. Then started the car without making
engine  ON and pressed the accelerator pedal full, I
found the butterfly valve is opening slowly. Almost 30
seconds needed to full open. But on the first try after
making key on it opened quickly. Later on same slow
response continued. While driving i used feel slow
acceleration. Cleaned throttle body with crc ibtake
cleaner but still problem continues.