If it was not for bad luck I would have none at all!

sorry to hear about the problems, dd72.
I also have a 2000 GC as my daily, but it has the 4.0. In it, the oil pressure pegs as soon as I start it. I'm guessing there's something wrong in the system, and not that the pressure is actually that high (kind of like slickchick said) so maybe yours is just an inaccurate reading (hopefully).