Hi tony im new to this site but here goes anyway......... turbos run very high pressures and this causes thing to loosen up a little to sum it up quite simply u need to check out the exhaust manifold for loose bolts the need to be from memory 27 newton meters tight but u need to check out the correct torquing of these exhaust manifold bolts this can cause the engine to shake and shudder and rough idle issues....the oxy senor will only calculate the richness or lean mixtures and send that info to the engine management systems to sort out the fuel mixture it wont cause what your stating in your comments....... hope this helps tony ....Bill.......
