In September, Ford offered the shield kits free for about 500,000 Crown Vic Police Interceptors, after a dozen officers died in fires caused by gas tank ruptures and fuel leaks over seven years.
The Center for Auto Safety wants California, Wisconsin, Virginia and Connecticut to force Ford to acknowledge the Crown Victoria and related models, the Mercury Grand Marquis and Lincoln Town Car, have safety or quality problems.
Those states have tough warranty laws requiring manufacturers to notify customers about safety problems and available repair campaigns to fix them.
The Washington-based consumer group claims Ford is offering the fuel tank shield repair kit well below cost in what amounts to a secret recall.
The gas tank on the Crown Victoria is located in a "crumple zone" between the car's rear bumper and rear axle. Engineers came up with the shield and an optional trunk package to keep articles from puncturing the fuel tank, after a three-month investigation by a technical task force and a nine-member blue-ribbon panel.
"Civilians ride at risk of a rear collision fire in the Crown Victorias," Clarence Ditlow, executive director of the Center for Auto Safety told the Detroit News. "They deserve to have the same protection police officers do."
Ditlow said the fuel-tank shield and plastic bumper cover together cost at least $300. Ford told the News there is no problem with the cars and that the kits were being offered at cost to consumers who want them.
The National Highway Traffic Safety Administration said gas tank fires involving 1993-2001 Crown Victoria and Mercury Grand Marquis vehicles have been linked to 38 deaths nationally.
Ford, which has lost $6.4 billion since 2001, reported a slight 0.1 percent drop in U.S. sales in February because of declining demand for its luxury brands -- Jaguar, Volvo and Range Rover.
Ford said it would likely cut second-quarter production after analyzing early March sales figures.
Notable deaths of 2014 [PHOTOS]