I would like to run regular unleaded in my recently purchased 2000 Navigator. I have a 1998 Navigator which I've ran 87 octane in since I've owned it with no problems so far. I know the 2000 has a higher horsepower rating and was concerned about any engine damage I might incur from running a lower octane gas than what is recommended by the manufacturer. I believe the 2000 still has a knock sensor and engine computer management to handle the octane situation, but want to be sure before changing over.