ok so i checked it again and i got code 71 which i believe is EGR system malfunction, but last week it said bad valve, and a few months before it said 02 sensor. i just dont know which to believe
Well, I would probably eliminate the O2 sensor for the time being, simply because of the time frame. What valve are we talking about? what code was it? I can't think of any codes that say you have a bad valve. You may have a short, or you may have multiple problems. Are you sure you're reading the flashes right?
