Magical oil leak

You say you've checked the pressure sender fittings, but have you checked the pressure sender itself for a leak that happens only while under running pressure?
I have an 86 Laser XT. There'd be a drop or 2 of oil under the car. I'd look for leaks, wipe & find nothing. When the leak finally got worse, I found it was spitting oil from the sender itself, but only after a spirited drive. Under pressure it leaked. New sender, problem gone.

HEY, just noticed I passed 1000 posts.