The National Highway Traffic Safety Administration was initially investigating 2010 Ford Fusion and Mercury Milan vehicles. Late last week, it said it also would look at those 2008 and 2009 models and the Lincoln MKZ.
NHTSA has gotten 52 complaints of accelerator pedals getting trapped by unsecured or stacked floor mats. No injuries have been reported. The investigation now covers around 480,000 vehicles. NHTSA investigations often lead to recalls.
Ford said it's disappointed that NHTSA is upgrading the investigation, because it involves aftermarket floor mats that were improperly installed. But the company said it will cooperate.
NHTSA said not all 2010 models are affected, since Ford introduced new pedals partway through that year.