Hi there, i have an Audi TT 180 coupe, when i start it from cold, the revs stay at above 1300 rpm and there is a sound from the front which sounds like the exhust is blowing, the reves drop after aprox 1 minute and the noise goes away. Is this normal? possibly an auto choke or self prrotection system maybe? Can anyone cnfirm this please. Thanks, Rich.