First, Make sure u have a small Cap on the power supply! (.1uF) . If that dose not fix it then ,

Add this after your "fuses"
DEFINE OSCCAL_1K 1

Change this:
SEROUT2 SER, 16780,["TEST" , 10] '2400 BAUD RATE
To
SerOut GPIO.4,N2400,["Test" ,10]