I need some help with faults. The car goes like a dream but has fault codes. I went to a garage who said a missfire was detected then reset the unit. It has since returned with a new code pointing to a "bank1 sensor 2 reading rich". Does this mean the sensor is faulty or that the sensor has picked up a fault elsewhere? Audi charge £90 for checking each time. I'd prefer to spend the money replacing fault! Would appreciate advice. Anyone else experienced this?