Trouble with Parallex GPS and Arduino Mega2560

chrispy4800:
still comes up with a repeated "y" in the serial monitor.

GPS.read() will return -1 if no characters are available to read. When that it sent to Serial Monitor it is displayed as character 255 (ÿ).

int value = GPS.read();
if (value != -1)
    Serial.write((char)value);