That's really odd after 5 hours of driving.

The only thing I can think of now is maybe the temp control for the heater core is malfunctioning...but that's unlikely to cause what you describe,

Check your water temp sensor on the drivers side cylinder head also.A incorrect reading will send the wrong signal.

 

does your heater temp change when all this happens? I'd be looking at the ect sensor and/or wiring

 

what is the ect sensor?

also, what does the temp sensor on the drivers side cylinder look like?

 

The problem ended up being with my intake manifold gaskets. They were basically tore to shreds. This started happening during cold weather. It would also stutter on idle.

I went and got new ones from the dealer since they changed the gaskets to a more durable one. Cost me $100. I went ahead and got new knock sensors too and the knock sensor cable. I spent over 250 on this, but now the engine coolant is normal even on cold temperatures and it wont stutter either. Just an FYI for others to learn from.