Gauge issues/heating issues/high oil pressure
 

Okay, so to start i'm driving a 94 ford ranger 4x4 xlt 4.0. The issue started a while back with the oil pressure reading high then followed by the temperature climbing rather high staying at that temp for a short time, perhaps a minute or two tops, then it drops back to to normal. So talked to a few people, came up with a quick check solution other then the obvious checking of fluids. Had the filter swapped to make sure it wasn't clogged. Once done truck continued to do the same thing. While waiting though i talked with the shop manager about other possible causes, he gave me the idea of checking the Sending Unit for the Temperature Gauge. Apparently, when the unit starts to go bad it messes with the gauges. I checked it all out turns out that wasn't the problem. What I did discover though was this particular part that I had previously thought may have been the problem, may in fact be the problem. Now here's the brick wall that I've come to. I own the repair manual for the truck and cannot find anything that tells me what it is, nor have the numerous part stores I've been too as well. I'm lead to believe its an Oil Pressure Unit, but everything I've seen tells me that it show be on the passenger side of the vehicle. Well this little part is driver side. Can anyone help me out? Seems the store's cant and I'd like to fix this issue. I have two photos but I cant guarantee they'll help, any kind of feed back is very appreciated.

No, that is an oil level sender

Should be drivers side towards the front by power steering pump.
Ford uses an oil pressure switch, on/off, so your description of the needle movement reads more like an electrical issue than sender issue.

I would first check the ground strap on the back of the drivers side head that goes to the firewall.
This is the ground for the instrument cluster, if loose or corroded it will cause high and changing readings.
Fuel and Amp gauges have their own grounds.

My '94 4.0l had random Temp gauge movement, it would go above 1/2 then back to normal(below 1/2), it had nothing to do with engine load, would just do it randomly.
Turned out on this model the heater core is the by-pass for the cooling system, so coolant flows thru the core all the time, core was getting plugged up causing the temp changes.
And heater was not blowing as hot as before, warm but not hot.
I back flushed it and things got better, but it still didn't blow as hot as before.
Turns out there are just 4 screws that hold the core under the dash so easy to change.
$28 for new core, and all is well.

I think this is the low oil switch; photo looks like maybe the wire is shorted ;frayed or broke; just a guess