TOYOTA drivers are claiming that their cars are speeding up by themselves -- even after they have been "fixed".
Sixty complaints have been received in the US after the car firm's recent recalls.
The National Highway Traffic Safety Administration said it was contacting every owner to learn more about the consumer reports.
The complaints, which are submitted online or through a NHTSA hot line, have not been independently verified. "We are determined to get to the bottom of this," NHTSA spokesman David Strickland said.
The new complaints, while small compared to the number of recalled cars, raise questions about whether Toyota's repairs will prevent reports of sudden unintended acceleration or if there could be electronic causes behind the safety issues.
The world's No 1 carmaker has recalled more than eight million vehicles worldwide to address accelerator pedals that can become sticky or trapped under floor mats.
NHTSA has linked 52 deaths to crashes allegedly caused by Toyota's acceleration problems.
Toyota dealers have been installing a metal piece the size of a stamp and shortening pedals to address the problems. But the government said if the remedy provided by Toyota was not addressing the issue, NHTSA could order Toyota to provide a different solution.
Toyota spokeswoman Martha Voss said the company had "rigorously tested the solutions for our recent recalls and we are confident with the repairs our dealerships are making".