I would have someone walk beside while backing up and locate the area, that will tell you where the problem is and probably you can figure out the rest.
Most likely the batter cables and posts are corroded . Just clean both batter posts and the cable ends that fit over the posts. Use the cleaner tool you can get at any auto store for not very much. It is steel brushes that fit over post and into the ends of the cables that fit over the posts...
Most likely the batter cables and posts are corroded . Just clean both batter posts and the cable ends that fit over the posts. Use the cleaner tool you can get at any auto store for not very much. It is steel brushes that fit over post and into the ends of the cables that fit over the posts...
Could be O2 sensor, I would put some very good gas additive in first and see if that will get any water out of the fuel and clean up everything inside.