i just got the 94 jeep and its the V8 with a newer engine and push button start. i tried to go and start it earlier and it would start and turn over and i could rev the engine but when i would get off the pedal and let it idle it would die and i dont know why it was doing that but eventually it started and was fine but then my aftermarket stereo would not turn on or light up or anything and i dont know what it is, if its a fuse or what? help me out