http://http://www.gminsidenews.com/f...showtopic=7706
The products that can contain the defective engines include the 2005 Ford Mustang GT, 2005 F-Series, 2005 F-Series Super Duty, Ford Expedition and Lincoln Navigator. Ford has instructed the assembly plants to stop shipping vehicles until they are screened to see if they contain the defective engines. It is not known if any products were shipped to consumers before the problem was noticed.
The 2005 model year 4.6L and 5.4L engines in question were built with defective cylinder heads. According to sources, the defective cylinder heads will have an adverse effect on performance and will cause the engine to fail to meet Ford's specifications.