Misfire.

[richyb66]

I've not tried the measuring block before but assume it's fairly straightforward?

I just did another scan aftger my 32 mile drive to work, no engine management light on but I got this:

VAG-COM Version: Release 409.1-US

Control Module Part Number: 4D0 907 559 A
Component and/or Version: 4.2L V8/5V G 0003
Software Coding: 10752
Work Shop Code: WSC 00000
Additional Info: WAUZZZ4BZ1N044499 AUZ7Z0Y1472110
4 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16689 - Cyl. 5 burn misfires recognized
P0305 - 35-00 - Please Register/Activate
16690 - Cyl. 6 burn misfires recognized
P0306 - 35-00 - Please Register/Activate
17537 - Fuel Trim: Bank 2 (Mult): System too Rich
P1129 - 35-00 - -

So still missing on 2 cyls and Bank 2 too rich so either it's over fuelling or it's an ignition fault thats causing the fuel not to be burnt.