Throttle Problem???

[Dan Ready]

Hi I'm new to the forum and I was looking for a little help and advice. I am driving a 2003, MITSUBISHI AIRTREK TURBO R EVOLUTION, and when driving it doesn't pickup the revs as it should do when you press the accelerator pedal. Does the throttle body need replacing, sensor problem or throttle body air idle control valve stepper motor!!

Any advice would be much appreciated.

Many thanks