Although I needed to replace the radiator cap, It was not the problem. I ended up taking it to a shop. They said the problem was bad grounds on the battery, engine, and tranny.

I found out it was electrical when I had been driving around and saw it jump up to H and back down. I turned off the car and tired to start it back up. The left side of my dash lights were all dim and the car wouldn't start. So I turned the key on and off over and over again until they all came on normal. The car would start up and be just fine for a little bit. The shop charged me $83 for an hour of labor.