Running lean on bank 2
 

Helping a friend out in oz has problems with a zs running lean on bank two, he's changed injectors, coils and plugs and still getting fault code, any ideas?

Faulty lambda?

If each bank has its own lambda sensor I'de look at that but first I'de look for an air leak on a vac hose ( or anything else air could get drawn in) on that side of the inlet manifold

Possible blockage or damage to the fuel rail???

lamda/02 sensor

Get the code, could be p0138 or p0141.

Isn't P0141 to do with the heater in the probe?

the fault code is p174, anyone know what that is?

Lean running bank 2 as you say.
Need to check lambda sensor in bank 2
Not sure if that's front or rear bank as I'm not sure how our engines cylinders are numbered but bank 2 is normally the bank without cylinder 1.

had a similar thing but posted about it over on XPF. if you do a search on P0174 over there its in the results.