Above is the video I just made demonstrating what my temperature gauge does. The needle gradually climbs all the way up (or hot) when the key is in accessory mode, when I go to start the car it drops back down to cold, then when starting the car it jumps up really fast to hot, then back down to cold where it stays while the engine is running.

What do you think is going on here? How easy might this be to fix? I've never worked on much automotive wiring before so I don't know what I'm getting myself into. There's a heatwave coming soon and I'd feel much better knowing my car is keeping cool-ish.

Thank you for your time!

 

Mine is the doing the same! I read in one of this threads that is the wiring is bad in the the temp send unit that sit between spark plug 1 and 3.