Why does old PIC draw too much current?
You say that 55 mA is "way out of specification", but you provide no evidence of that.  It seems to me you haven't bothered to look in the datasheet.  You also haven't said which PIC 24.

I grabbed a random PIC 24H datasheet and looked up Vdd current.  The PIC 24HJ12GP201, for example, can draw up to 90 mA at 3.3 V and 25&deg;C when running at 40 MIPS.  55 mA is therefore not at all obviously "way out of specification".

READ THE DATASHEET.