Is the car equipped with other senser that would cause the condition described below,?

A few week ago, I went to turn on the engine and the engine light came on and the engine would not idle without me keeping my foot on the gas. After several minutes the idling became steadier but you can  see white smoke coming out of the exhaust and the odor  was very strong.  The mechanic told me that the air flow sensor which had been replaced a year ago needed to be replaced again.