A: Have the high tension electricals of your car checked thoroughly. What you describe sounds like a failing HT coil or alternatively, problems with the ignition/electronic control module. The temperature gauge typically monitors only engine temp and doesn't keep an eye on other individual components. There is a degree of thermal efficiency to each component in a car and with age, they could fail. Even spark plugs fail and regain their spark once things cool down. Check the ignition system thoroughly