Re: jeep problems
U0100 according the the VERY brief search I did is no communication with the PCM. This could be any number of things. Ultimately I have no silver bullets for you. The fact that it starts, even for a moment, leads me to believe there is power and grounds present to the PCM as running even for a second requires PCM operation to command ignition and injectors. If the PCM is not on the bus though it may be triggering antitheft and shutting the vehicle off. Do you have a red light flashing or any message that may indicate antitheft operation?
2005 Jeep Grand Cherokee - Gone but not forgotten!