Resistor low as 472 Ohms looks suspicious to me.
Have you checked MCLR pullup resistor (for instance 4.7k)?

16f54 is specified upto 20 MHz.
I don't think 20 MHz is possible using RC.
the RC oscillator on the PICs is only designed for low frequency (some MHz at best).

There is alternative way: use RF inductor (HS mode), values low as 22uH possible but somewhere there is margin when there is no more oscillation.

Due to high tolerance/temperature affection of small ceramic capacitors, I don't use RC at all.