Overheating and cooling while driving.
MY ISSUE:
So I drove the truck off the lot today and about 3 miles down the road I saw the temperature gauge spike into the red, so I pulled over and the truck almost immediately cooled down to a normal temperature. I was alarmed so I check all over the engine and there wasn't any coolant leaking or bubbling in the overflow reservoir. So I got back in the truck and kept driving. Another mile down the road, it overheated again. This time I let off the gas and it cooled down to the middle of the gauge, so I kept going. The gauge repeated this fluctuation the whole way home. What could it be? Is the thermostat sticking?
Any information would be helpful. This is supposed to be my work truck and I need to get to work. I can't have an overheating engine. HELP!
DJ



