It would be nice if you could graph your data as you SLOWLY press the accel pedal. See if there are any gaps or spikes in the data.
As weird as it might be, my pedal is MOST finicky when its cold and I have heat blowing on my feet from the HVAC. As if it unevenly heats up the sensor giving erratic results.
Usually you should see a rational code set for this. I cannot remember the exact name of it.