Let just get to meat of the matter. 93 SC drivers side bank plugs are covered in soot passengers side are clean (plugs have less than 50miles on them). Engine is lacking power, not devolping full vaccum/boost; replaced Fuel filter, plugs, wires, Ingition Module and Coil pack. I'm now leaning toward a oxygen Sensor being faulty (age is unknown I have had the car for less than a year).
Am I correct in thinking oxygen sensor (my understanding of EFI tells me that if any other sensor was faulty would be both banks)?