One problem related to power train has been reported for the 1999 Mercury Mountaineer. The most recently reported issues are listed below.
The contact owns a 1999 Mercury Mountaineer. The contact stated that while driving at 30 mph, the check engine warning light illuminated. The failure occurred on multiple occasions. The vehicle was taken to an independent mechanic where it was diagnosed that the spark plugs needed to be replaced. The vehicle was repaired but the failure persisted. The manufacturer was not notified of the failure. The VIN was not available. The approximate failure mileage of the vehicle was 128,000.