Today im driving and i noticed that it seemed as if my speed would't kick in correctly. I could also tell by how the rpm gage was going. I parked, kept the air running as I went into the store. When I came back there was a message on the dashboard that read " your ac was turned off due to an overheated engine"! I looked at the temperature gage and it was almost on the H! So i turned the car off and then back on, as I started to drive the gage goes back to its normal state and the air came back on, what is wrong with my car?