Hi all, i've got a 53 plate 4.2 S4, BBK engine code, it's misfiring like hell. Have had a scanner on it and keeps coming up with codes as follows, 17755 Bank 2 camshaft/crank angle sensor wrong combination of ecu's p1347 17748 camshaft/crank angle sensor wrong combination of ecu's p1340. These codes can be cleared but when started again they come back within minutes. Eventually misfire codes for all eight cylinders appear!! Can anyone shed any light on this? have been told by one person that the timing chains need to be changed!! Help please!!