House lawmakers investigating Toyota's massive recalls say the company is more focused on discrediting its critics than trying to solve problems of vehicles suddenly accelerating.

Rep. Bart Stupak, D-Mich., says Toyota has tried to damage the credibility of an Illinois engineering professor who testified at a February congressional hearing that he had recreated sudden acceleration in a Toyota.

Stupak says at a House hearing Thursday that Toyota hired a polling firm to learn more about what it could do to repair damage to the company's image. And he calls a Toyota consulting firm's report on the professor's research a "hit job, not solid science."

Toyota's top U.S. sales executive, meanwhile, plans to tell the panel that the automaker believes faulty electronics are not to blame for unintended accelerations.