One company has become on advocate for consumers, calling for the government to explain how it will deal with used cars in New Jersey and elsewhere that were traded in as part of the Cash for Clunkers program but are no longer eligible because of revised fuel mileage numbers from the EPA.

Edmunds.com had previously shed light on the fact that the pool of less fuel-efficient cars had shrunk, even though many were originally listed at the maximum of 18 mpg when they were sold, because the federal government refreshed the numbers and made several models ineligible.

But the program was already running for three weeks when those updated ratings were announced, and Transportation Department spokesperson Rae Tyson said, “We’re evaluating our options, [although our] mandate is clear and based on fuel economy ratings.”

“Consumers acting in good faith should not be penalized for undisclosed and last-minute changes made by the government,” said Kevin Smith, Edmunds.com editorial director. The company wonders whether consumers will have to forgo the savings they had expected.