Engine cut-out

When cold, the engine cuts-out during light acceleration, and does so occasionally until fully warm.
It is like spark or fuel is temporarily gone, then rapidly returns.

Problem is getting worse.
This has been going on for weeks now, but would never happen when I was leaving work at night, only after first start of the day, when leaving for work in the afternoon. Recently, it started doing it at night when leaving work, too.

It was not ever happening when I was accelerating a little harder, when getting on the freeway, however, that recently happened.
I noticed recently, that if I am looking at the tachometer when it occurs, the tachometer jumps up pretty high, then back to normal when it's running again.
I would think it would drop to zero, not jump upward!
I recently found my scanner after moving, and plugged it in, there was no check engine light ever, but found a fault code: P1189 "Engine Oil Pressure Switch Circuit"
It does seem possible, that if the computer sees no oil pressure, it might shut the engine down, but then it is running again, just that quickly. I would think if it saw no oil pressure and shut it down, it would not restart in its own. I have never yet had to engage the starter to get it running again. It just resumes running again, as if ignition or fuel suddenly returned.
To be safe, I picked-up a new pressure switch, but for a few days now, I have checked for the code to return, and it has not.

Any ideas?
It seems odd to me, that it never happens when fully warmed-up, but it happens much more frequently now, when cold or only partially warm.