Let me guess... P0220 ?
White Multi-plug under the passenger side dash behind the glove box, follow the cable towards the pedal assembly.
Although, if you are having issues, it is more than likely two things:
The throttle body butterfly sticking with oily deposits preventing proper full range of motion... Carb cleaner and then the lightest oiling with WD40 on the spindle pin where it enters either side the outer body will suffice but DON'T move the butterfly by hand
, get a helper with ignition on to press the accelerator pedal down and up while spraying. You can carefully use a cloth to clean off the excess deposits while the throttle is fully open.
The Throttle Potentiometer Multi-plug, these can be problematic as a connector itself can work loose or even the pins can be loose. Clean off the spades with electrical contact cleaner, fit back together and between both halves of the plug and the wires, run a small cable tie between the wires and secure both plug ends together to prevent movement and loss of signal between the spade contact points.
For what its worth, perform both fixes first before going to the expense of replacement items, just in case... Its a maximum of £10 for the spray tins if you don't already have them... A lot cheaper than a throttle pedal assembly or throttle potentiometer sensor.
Finish off with a throttle reset procedure for good measure