Mine says 2%. If you adjust the idle screw, it will change a little. If it went to zero, that would mean the butterfly is totally closed, no air, no fuel, no nice noises from the exhaust.
As for the TPS map on the PC2, DynoJet says don't touch it without calling them. It changes the trottle position sent to the ECM which will in turn change the amount of fuel (injection duration) to go along with the air the ECM thinks will accompany it.