Why is the engine troubleshoot not working engine does not stay on?

If, as soon as you start engine it shots off, the there might be a problem with fuel delivery to the engine, which could be a loss of significant fuel pressure, and or an ignition switch thats going bad. Usually on these vehicles its the ignition switch go bad most of the time. However, it doesnt mean it could also be a fuel delivery problem, like your injectors are clugged or the fuel filter is clugged. But, i would go first for the ignition switch. The ignition switch is underneath steering wheel, just have a mechanic check the resistance and to see if any volts go though it. Then, if its not the ignition switch, tell mechanic to check fuel pressure. But you can check it yourself, by losening upper bolt on fuel filter, this releases pressure, have a rag ready to pick up fuel, as it may pour out, then turn key or have someone turn key to ON position but DO NOT crank engine, if fuel comes out like its suppossed to then stops, like its designed to do that, then your problem its not fuel delivery to the engine, but if nothing comes out, then you got a problem. But do this with great caution as this is dangerous. Hope it helps.