daanno

I've got a curious problem that I'm trying it figure out. For the past 3 days, my cold-start oil pressure is close to 100 psi (around 1100 rpm). It's usually around 75 psi at start and drops within a few minutes as expected when the engine warms up. It now takes about 15 minutes to settle into the normal pattern. I've been just letting it idle for 10 minutes until I feel that it's "safe" and then tip-toe on my way until it reaches it's "normal" state.
Here is a quick run-down of what has been normal for my car (91 accord).
750 rpm 10-15 psi
1500 rpm 38 psi
2000 rpm 62 psi
2500 rpm 75 psi
3000 rpm 85 psi

Here's a little relevant history:
January- replace: front seals, timing belts, water pump, oil pump, and all the misc gaskets, Installed an aftermarket electrical oil pressure gauge.
Symptom free for 17,000 miles.
The usual maintenance is done regularly.
So... my big questions are... What is the likelihood that this is an "instrument or sensor" issue? and... if not... Where should I start looking?
I did an oil and filter change two nights ago (thinking it might be a clogged filter) but no change in the symptoms. I'm hoping that it might be a possible clogged PCV valve or clogged oil pick-up (relatively easy remedy). I'm just looking for a few ideas.
As a side note, this is not the circuit that feeds the oil pressure light on the instrument cluster. This is "add-on" gauge that operates independently from the on-board computer. And, for clarification, this started happening before the oil change.

WOW, I didn't mean to write an epic. Any advise is welcome
Thanks
Dan