Hmmm... how much Test Equipment, time and patience have you got???

(1) If you have a Frequency Counter, program for INTOSC CLKOUT and measure fosc/4 on the GPIO.4 OSCOUT pin. Adjust for 1MHz.

(2) If you don't have a frequency counter, SEROUT a Test Message at say 9600 baud to your PC. Keep adjusting the value until sensible data is reliably copied onto say your PC's Hyperterminal.

(3) Save yourself $500 worth of effort, spend $1 and buy yourself a new PIC.