[AWP9521]

Is the Check Engine light on? Usually cam and crank sensors going bad should trigger it. Lets check the car for fault codes by doing the following.

Put the key in the ignition and turn the key to the on position then off, back to on, then off and back to on again in rapid sucession and then observe the Check Engine light.

When the light goes out it will begin to flash on and off slowly, then a longer off pause then flash again, count the on flashes and write the number down, two flashing events represent a 2 digit fault code (Ex: on-off-on-off-on-off pause = 3, on-off-on-off-on-off-on-off-on-off pause = 5 the code would be 35), keep watching the light until the flashes of the CE light stops (stays off). Then shut the key off for 1 minute and repeat the process again to make certain you have the codes correct.

Any code other than 55 (End of message code) is a valid fault code, if any codes show with this procedure post them here and then well see what they are and hopefully get to the root of the problem.

Your friend may be right on his assumption with the key switch, they do tend to have problems with them going bad (I have replaced 2 so far on 2 different vehicles) but you are saying that only the engine is shutting down and not any other power accessory that is in the same circuit as the ignition system (such as the HVAC system, Turn Signals, Gauges, Power Windows, Wipers, etc.) if that isn't happening then I would not question the key switch just yet.

So lets start with checking the fault codes and go from there.