1987 2.3 GAS, I THINK I read them right, I got a 31 and a 67, the 67 went away after I pulled the neg cable from the battery. I went and got a new EGR Position Sensor, 31 is still coming up. also, would an 87 also have the 3 digit codes, I THINK I'm also getting a 112, but I am not sure if I am...