ok so im at a loss. when i went to start my jeep up last night it was fine so i shut it off but had to turn it on again to move it and nothing it was almost like the battery was dead but the gauges fluttered up and down really quickly. when i turned it to the on position i adjusted the gear shift and put it in drive and back into park and power came back (was already in park when wouldnt start). im not sure why this is and sometimes when i go to start it the engine will start up but stumbles on its self. any ideas what the problems are?

thank you for any help you can give

 

It happen to me one time. I torque the battery connection and problem went away.