A few days ago I was driving and my check engine light came on. I got on the internet looking for solutions and came up with the conclusion that it couldve been bad fuel so I added a gas treatment and after a couple of hours the light went off. A few days later the light returned and I added another treatment and again after a few hours it went off. Now today im driving and the car starts to accelerate slowly and the engine light comes on and the temperture gauge is at the highest point. I noticed that it gets that way after the gas gets pass the half a tank mark. What could be the problem?