Overheating s-10 4.3 1991

I don't drive my truck much but last week I was on the hiway going about 65 and all of a sudden my temp gauge went to over 290 degrees and the display said check gauges. I went to turn off the freeway but after a couple of minutes it changed back to 190 degrees and was fine the rest of the drive (about 30 miles). Then, coming home on the same hiway it did it again for about a minute and returned to 190. Could this be a thermostat problem? Or the beginnings of a head gasket problem? Or something else? Please help. Thanks so much

Did the overflow bottle fill-up? Usually, if it gets too hot, it will pop the radiator cap. The overflow bottle will fill up in a hurry. Replacing the thermostat and radiator cap won't hurt a thing. Are you losing coolant?

I didn't check under the hood until after I got to my destination because the temp had gone down. Then there was nothing in the reservour bottle which was also empty before. I checked the radiator when it cooled down and added 1 quart of water.

The overflow bottle, where applicable, has a fill mark on it, put some antifreeze in it.

290 would blow a hose. I think you have a gauge problem.

I was mistaken, the temp gauge only goes to 260 degrees...I will add antifreeze to the reservoir bottle today.