Please tell me if I should use "brake pedal" or "brake pedals" in the following sentence.
"A recent report revealed that a certain manufacturer's automobiles accelerated even when the brake pedal was pushed."
It should be singular (brake pedal) because each car only has one pedal. I suppose that you might want to consider using the plural, since you are speaking of multiple automobiles. However, using the plural could lead to conclusion, since we might wonder whether that particular automobile company's automobiles might have more than one pedal. Keep it singular. It does make sense.