First, it is a good idea to turn off/disable the comparators:
from the data sheet
8.2.1
COMPARATOR ENABLE
Setting the CxON bit of the CMxCON0 register enables
the comparator for operation. Clearing the CxON bit
disables the comparator resulting in minimum current
consumption.
Then, if you are using a 10MHz external, do not use the OSCCON register.
If using the internal then set OSCCON to 01110000 for 8MHz.