[rogoman]

While driving the car at normal highway speeds, if it has a tendency to jump out of OD and then back in, that generally indicates a TPS problem. The TPS has an electrical resistance strip inside that has a bad spot on it. If you have access to an ohm meter, you then determine if indeed there is a bad spot; if so, the TPS cannot be repaired. You'll have to get a new unit from a Nissan dealer.