i have a 1993 300zx n/a and we have done a motor swap just dropped another of the same motor in had to get another wiring harness as well. when all was said and done the car ran great for a couple weeks but now runs extremely rich went to run the codes on the comp but nothing came up the check engine light is on but is not pulling any codes. so we had the comp rebuilt and still same problems. could this be causing my car to run rich