Hi i'm new here and i am working with a friends grand prix, its a 2002 with a 3.1, To make a long story short he had a used engine installed and now the trans starts in high gear, and it will not communicate with the scanner. I've checked all the fuses, grounds (that i can find) connections and fusible links. I replaced the o2 sensor on the back manifold as it had 3 wires cut. I thought to come here and see if any of you have run into such a problem before. So i will appreciate any ideas you can give me, and if you can tell me the location of all the main grounds so i can make sure they are all there. Once again thanks for any help.
