this Toby from Germany. I have a 2008 Avalanche LTZ and probably a problem with the ECM or the wiring. After we changed a bad alternator the engine light began to blink, also the "service stabiltrak and traction control" With the OBD my garage found out that there are a lot of misfires on the 6. cylinder. They substituted the ignition coils with always the same effect. They are quite sure that there is a problem with the wiring or the ECM. But we can't check that easily because we don't have the engine wiring diagram and we can't find it here in Germany. Can anyone pleaaaaasssee help me?!