Hi Paul i too had a similar problem, the coil replacement on the one bank is fiddly but not too bad, on bank 2 its a bit of a faff due to removing the manifold, if you change them take one of the old ones off first and check the connections, i didn`t do this and was sent a two prong connection off e bay which was supposed to fit when I needed a four prong, got the money refunded but if this saves anyone the same agro then I think i Iwill have done you a service, if you can get a cheap code reader this can help pin point lots of these types of faults.