Might be time to have the system sucked down, replace the expansion valve, and fill it up with new freon and oil. It's a good idea to do this every once in a while. The expansion valve not opening fully is a common cause of the increase in pressure.
2003 WJ in Jeep Green Metallic
, 4.0/242/4.10's. 4" Teraflex springs w/ RE monotube shocks and IRO short arms, cheap intake w/ amsoil filter, 2.5" hi flow cat and back exhaust, lots of lights and other misc crap.
Check out my build thread here: Life lessons and budget build