Jeep Repair: will not stay running, Christian Customs jeep shuting off

Question
Turn key to start it starts, let key go  to run, it's turns off can you help me. 1990 jeep charkee

Answer
OK this is tricky, Does it feel liek the key switch is loose at all, and maybe when you are letting go of the keys it is thinking that you are turing it to the off postion? Go out to your jeep Start it up and let it shut off, then go and open your gas cap and see if you can hear the fuel pump still running, If you can then something is wrong with the fuel system, but if its off then its in the key switch, Hope this helps.