I do not know who asked the question and the technical level of the person asking so I have given you an explanation as per your question.
Which engine do you have?
The problem is a fault with the A/F (Air/Fuel) sensor, meaning the Oxygen sensor, and it most lrobably is bad. You would need to perform testings to verify if it is the sensor or its circuit that is causing the problem.
The sensor is located on the exhaust after the manifold.
Tuesday, November 20th, 2012 AT 1:11 PM