NEW YORK — Toyota built its reputation in the U.S. as a maker of safe and dependable vehicles, but the quality of the Japanese automaker's fleet continues to be tarnished by serious safety recalls.

Toyota said Thursday it is recalling 2.3 million vehicles in the U.S. to fix accelerator pedals with mechanical problems that could cause them to become stuck. The announcement comes just months after it recalled 4.2 million vehicles because of gas pedals that could become trapped under floor mats, causing sudden acceleration. That problem was the cause of several crashes, including some fatalities.

Toyota said Thursday's recall is because of potential problems with the gas pedal mechanism that can cause the accelerator to become stuck — regardless of whether the vehicle contains a floor mat. Toyota said in certain rare cases, the gas pedal mechanism wears down, causing the accelerator to become harder to press, slower to return or, in some cases, stuck.

In a letter to federal safety officials dated Thursday, Toyota said the problem appeared to be related to the potential buildup of condensation on sliding surfaces in the accelerator system that helps drivers push down or release the gas pedal.

Toyota spokesman John Hanson said the automaker does not yet have a solution to the latest problem but is working to develop one. Toyota will soon be contacting owners directly about the recall, he said.

The recall affects the 2009-10 RAV4, the 2009-10 Corolla, the 2009-10 Matrix, the 2005-10 Avalon, the 2007-10 Camry, the 2010 Highlander, the 2007-10 Tundra and the 2008-10 Sequoia. Of these, the Avalon, Camry and Tundra models — encompassing about 1.7 million vehicles — also were included in the previous gas pedal recall.

Toyota said drivers in the recalled vehicles whose gas pedals become stuck should firmly apply their brakes, drive the car to a safe location, shut off the engine and contact the nearest Toyota dealer.