I had a 2001 GT that had similar issues. It started out that my oil pressure gauge needle would not move for about a minute after start up. Gradually got worse over the next month or two and would take longer for the needle to move to normal. No ticking or knocking. One day made it a couple blocks from home and started ticking bad. Immediately brought it home.
We all know about the oil pressure sensor issues, and that was what I expected. Always full of oil and never any engine noise. Just lucky this day I wasnt far from home, had windows down, and radio off. If not engine would have been toast.
Prognosis: Changed oil pump and found oil pick-up full of crap. You wouldn't believe, an I still don't, how much junk I pulled out of the pick-up.
Put it all back together and never changed the oil pressure sender. Ran like a champ!
If nothing else, you could pull the sender and connect a real oil pressure gauge to ensure its getting good pressure and the install a new sender. Depends on what you can afford.