Based on your first post,
“Goes up for couple minutes, then comes back to normal”
it seeme like there is something that has clogged the small flow holes in T-stat and doesn’t let hot water go trough soon enough to open it, (I have seen this happen),
or just an old or lazy T-stat that doesn’t work right any more,,
if you don’t know how old it is , just replace with a new 180* unit, and see if that will fix problem,,
(& then you need to bleed system properly to make it work right)
if you don’t know how to do it,
take to someone who does & have them replace T-stat for you.

 

But when you get this fixed I would suggest you do a lot of reading here. And the things you should do ASAP to avoid headaches

 

Let's do some simple research.

Do you have coolant in the bottle?

Do you see the bleed screw on the front hose or at the T at the alternator?

On amazon, there are cheap obd2 readers. These work with your cell phone and allow you to watch your temps.

When was the last time anyone touched your coolant?

 

I had the same problem before with my D2 04 V8 4.0L

turned out the coolant container (pump) hose that was suppose to bring back the coolant into it was not working 100% (coolant cycle dirty)

i changed the pump not the hose and the problem is 100% gone .

before all of this normally my car was running at 208°F - 98°C for a normal day drive
and all of sudden it goes up to 242F - 117°C and then it goes back to 208°F - 98°C

i use an OBD2 Bluetooth just to keep my eye on the Temp all the time.

i changed the thermostat more than ones and i even thought to use a TD5 thermostat just to keep the temp below 194°F - 90°C.

with the new pump and new thermostat it runs fine now at 177°F - 81°C.