My truck is acting really strange with the cooling gauge. I will be driving down the road and my temp gauge will show I am overheating and my truck turns on the check gauges light. After about 30 seconds it falls back to normal. I am thinking my thermostat is going bad. Is it that or a sensor? Any ideas?

 

Well I would say change the thermostat and flush the system out. While your at it inspect the fan clutch to be sure is ingaging when needed.

But if you getting hot and then dropping I wouls say the t-stat is shot and sticking closed and popping open at the last second...

 

I agree with Mopar. Pull the T-stat and put in a 180 it will be better for the truck.