My car just won't start except when the engine symbol appears and when the key is in the 'On' position - then the car starts, however it will stall at any time without warning. Your advice would be greatly appreciated as to what is causing this.
The engine symbol is the Check Engine Light. Like all of the other lights, the Check Engine Light should illuminate briefly when the key is turned to the accessory or on position. This is done to provide a self-test of the bulbs. The Check Engine Light will then stay on if there is a problem in the system. So the fact that the vehicle only starts when the Check Engine Light is on sounds like normal operation.
As far as the stalling out, there are countless potential causes. It could be anything from a vacuum leak or a failed sensor. I suggest you have a professional, such as one from YourMechanic, diagnose your stalling issue firsthand, so that a correct repair can be made.