General Motors says it recalled 3.4 million large cars last month after finding a 9-year-old email from an employee in its files warning of trouble.
The admission is more evidence that GM knew about safety problems for years but failed to recall cars until recently.
The company didn't recall the cars when it got the email in 2005.
But it decided to call them in for repairs last month after finding the old email in its files in an April search.
In the email, an employee who was testing a 2006 Chevrolet Impala before production reported that the engine stalled and a technician blamed it on a faulty ignition switch.
The email was detailed in documents released Thursday by the National Highway Traffic Safety Administration.
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