Ignition Coils Failure problems of the 2004 Lincoln Aviator

The contact owns a 2004 Lincoln Aviator. While driving at approximately 55 mph, the check engine light illuminated on the dashboard. The vehicle was taken to an authorized dealer where the contact was informed the ignition coil needed to be replaced. The ignition coil was replaced. Approximately 4 months later the failure recurred. The vehicle was again taken to an authorized dealer where the ignition coil was replaced. The failure continued to recur on several other ignition coils, and the contact replaced them himself. The contact stated that the failure continues to recur. The failure mileage was 21,000 and the current mileage was 144,000.