If you are experiencing any problems with a bad idle condition or low speed miss, check the connection to the Throttle Position Sensor.
When the wire tap is correctly installed, it MUST NOT cut into the wire. It should cut only the insulation. If it does cut into the wire, the bike will run OK until the PCIII is plugged in. Then the added resistance of the PCIII will cause the throttle position to be mis-read by the ECU.
To correct the problem. 1) Disconnect the wire tap. 2) Repair the wire on the bike (center yellow). 3) Reinstall the wire tap. 4) Haul ass.