99 Explorer Stutters

[ScExplorer1]

My daughter just bought a 1999 Explorer V8 5.0, and if you turn on anything electrical (AC, heater, headlights) while you are driving the vehicle will start to jerk, stutter or skip but without any electrical load it runs great. It is showing no codes. I have replaced the fuel filter, plugs, and coil packs which has made no difference. Does anyone know what I need to try next?

 

[Vic_Ferrari2002]

Getting the Battery and/or Alternator tested at your local auto parts store would be my first step