WASHINGTON — Toyota said this morning its dealers should get parts to fix a sticky gas pedal problem by the end this week as the automaker apologized to Toyota owners and tries to bring an end to a recall that has affected 4.2 million vehicles worldwide.

The company said in a statement that it has begun shipping parts and is training dealers on the repairs.

Technical bulletins on how to install the new parts should arrive at dealers by midweek, the company told dealers in an e-mail. It was not clear exactly when repairs would start, although dealers have said they'll begin as soon as possible.

The automaker also said Monday it would suspend production of eight U.S. models affected by the recall for this week. The company suspended sales of the models last week until repairs can be made.

Engineers traced the problem to a friction device in the assembly that is supposed to provide the proper pedal "feel" by adding resistance, Toyota said in a statement.

The device has a shoe that rubs against a nearby metal surface during normal pedal use. But wear and environmental conditions can over time cause the pedals to not operate smoothly or in rare cases stick partially open.

The company said a steel reinforcement bar will be installed into the gas pedal assembly, reducing the friction.