(March 5, 2010) About 731 owners of Toyota vehicles not covered by two recent recalls have reported sudden acceleration complaints to U.S. auto safety regulators in the past six weeks, a Detroit Free Press analysis has found.

The growing crowd of complaints, representing about half of the 1,460 received by the National Highway Traffic Safety Administration since Jan. 15 about Toyota models and sudden acceleration, adds to evidence that Toyota still hasn't identified all possible causes of the problem, The Free Press reported.

NHTSA also said it had identified 10 complaints from Toyota owners who had vehicles fixed under recall only to have sudden unintended acceleration again. The agency said it was calling those owners for details.

"If Toyota owners are still experiencing sudden acceleration incidents after taking their cars to the dealership, we want to know about it," said NHTSA Administrator David Strickland in a statement.

Under growing pressure from Congress, NHTSA has launched three probes into whether Toyota was slow to alert regulators to safety defects, and whether its recalls cover enough models.