I have an opel corsa 1.4i lite, When it stands and idle it will idle the radiator fan will come on all is fine. But as soon as I drive the car and it is hot it cuts out. Some times it starts first tome sometomes I have to wait 10 min. This is intermittent. I have change the coil pack, feul pump relay checked the fuel pump oressure all ok. What could be the problem?