why misfiring cylinder #4&#7...why air conditioning compressor will not kick on? on 2002 Dodge Ram Van 1500

recently replaced spark plug wires, ignition coil, cap & rotor, but still major loss of power...misfiring upon shifting into any gear/

Asked by for the 2002 Dodge Ram Van 1500
Who did the work? Plug wires routed right? Misfire at road speed?
May need freon in AC system.