Faulty TPS sensor, the signal should range from .45V closed to 4.5V WOT, having 5.04V at WOT indicates the arm inside the sensor is not touching the resistance tracks. If you hook up an OBD scan tool, your code should be one of these.

P0121 Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem
P0123 Throttle/Pedal Position Sensor/Switch A Circuit High Input