I have gone through some crazy stuff with my 1997 Nissan Pathfinder SE 4WD. All oxygen Sensors reporting even after replacement. Problem with the fuel gauge ect. Only P0500 right now but what helped solve the Gremlins was to remove the Spedo cluster and loosen all screws and then Tighten the shit out of them. I had removed the spedo unit 3 times before. I was so pissed that I tighten the shit out of them and that worked, just don't break anything. Hope this helps you. How did you make out with the P0500?