Oil pressure question and stutter update

[max29a]

Hello yet again,

First a quick update: been having stuttering/rpm loss issues since I bought the car, getting worse and worse. I finally noticed that when its dead the tach doesnt move at all when I crank so I thought speed and ref sensors. I orderd some used off ebay 2 for $100. Well they came in the bracket and 1 would not come out. So I only replaced 1. Now it runs much better. Once it is warm it hardly ever stutters, yet it still does occaisionally. Now its down to once a day or every 2 days whereas before replacement it was almost undriveable. I also cleaned the engine grounds while I was in there, don't know if that could have been the actual problem. I suspect I actually have or did have multiple problems as I used to hear a relay click every single time the car died or came back but now I never hear a relay click, and instead of dying it just stutters, whereas it used to die a lot.

Next up:
I had thought that my oil pressure sender was dead. I bought a brand new one and replaced it and the gauge always reads between 0 and 1 at all times. When car is first turned on and cold it will stay at 1 and then as it warms up etc drop towards 0. If I am cruising with higher rpms it will climb back to 1.

My question is what does this mean? what may need replacing, and how bad is this? what kind of damage is being done, or is going to be done?

I have searched a bit and come across the oil pressure relief valve but I do not really understand what all is going on here, so some more help would be appreciated.

Finally lots of thanks are due to Danno, as he has been helping me what seems like every other day. I replaced the thermostat under his guidance and it made all the difference in the world.