The oil pressure guage on my 1993 Park Avenue is almost permanently way off the scale (at the high end) When idling it is right at the high end of the scale, but as soon as I accelerate it goes way off the scale. Any suggestions as to why this is happening - and is it a problem?

Most likely the sending unit.

Search the archives for "oil pressure" This is the thread that talks about it best.
http://www.automotiveforums.com/vbulletin/showthread.php?t=313691&highlight=oil+pressure
hope this helps. Brian in IN

Thanks for the responses. Just had a new sending unit installed - now everything is fine.