As the cars runs, it reaches 80km/hr it starts.

As the cars runs, it reaches 80km/hr it starts shaking with the RPM falling up and down until it all over a sudden the engine stops. When it stops, it takes a little while (abt 10 - 30minutes) to start again. It also does this if it is at a very low speed (abt 15km/hr) especially when it was running before. At this point the temperature meter is still ok at midway the scale or even slightly below the mid way scale.

When I disable the temperature sensor, the engine does not stop.