haitham

i have audi allroad 2001 and on the scanner there is misfire in cylinders 1-2-3 and some times it appear exhaust temperature sensor fault can i know where is the problem ? the told me that the exhaust temperature sensor is damaged and need to replaced, i put the car on scanner more the one time, the exhaust temperature sensor dose not appear all times and some times fuel goes out of the exhaust.
can some help me to diagnose the issue ?