The contact owns a 2003 Lincoln Navigator. While driving at 35 mph, the check engine light illuminated. When the contact depressed the accelerator pedal, the vehicle would not move forward but then after a few seconds, suddenly take off. The vehicle was taken to an authorized dealership where the contact was informed that the failure was caused by a vacuum leak. The coils and spark plugs were replaced but the failure occurred a day later. The failure reoccurred twice but had not occurred since. The failure mileage was approximately 105,000. The current mileage was approximately 118,000.

- Hyde Park, MA, USA

I bought a used 2003 Lincoln Navigator with a big 5.4-liter V-8 engine from wittmeier Ford in chico, ca. In 2004. The Navigator looked like a great deal. The price was $43,000. The Navigator had only 23,000 miles on the odometer. But the great deal blew up in my face when the used Lincoln Navigator spit a spark plug at 81,000 miles. The check engine light came on as the truck began to lose power. As we drove the car it continued to back fire. The ignition pack for that plug was shredded. I called wittmeier service and they said they knew nothing of the problem. The threads in the number 3 spark plug hole in the Navigator were stripped. We needed to re-thread the number 3 spark plug hole and replace the ignition pack. I read on the internet where this is a common problem and it will likely happen again. I believe Ford should take care of this problem.

- Paradise, CA, USA

My 2003 Lincoln Navigator ultimate @ 84,000 miles blew 2 spark plugs through the aluminum head of the 5.4 liter Triton engine. It is my understanding that this aluminum head has been redesigned by Ford and that there is also an after-market fix to this increasing problem that re-threads the spark plugs, but that said fix also gets forced through said inadequately engineered aluminum head. For refuses to pay for the replacement of said head and said repair is estimated in the thousands of dollars. I replaced the melted coil and barely was able to thread new plugs into place, but I am concerned about being stranded somewhere in my car. I think that Ford should have to recall all of these engines and replace the old heads with new, better engineered heads.

- Duluth, MN, USA

Without warning the vehicle stalled while the consumer was driving at an undetermined speed. The consumer contacted the dealer on four separate occasions and the problem still continued. When idling the vehicle made a pressure like noise that would get louder, the low oil indicator light would come on, the valves had a tapping sound that was abnormal, there was a metal scraping sound which as if the bottom was going to drop out, there were exhaust noises along with a popping sound, and there was continuous stalling. The consumer stated there was an ongoing dispute regarding the odometer reading. Also the brakes and door locked never worked.

- Bartow, FL, USA