[ainarssems]

noticed on goup 001 that the two lamda banks were vastly different minute or so after starting. like -10 and 18. Once the engine light was flashing and missfires detected they went to 0 and 0

That definitively sounds like valve timing problem. One bank is getting 57% of air and other 43% (normal is 49-51%). Lambda control tries to adjust fuelling accordingly giving extra 18% fuel on one side and cutting 10% on the other side. Then after a while it gives up and goes 'open loop' because of excessive adjustment needed, this is when you see it go to '0'. I think threshold for it going 'open loop' is around 16%( acceptable is considered -12.5..+12.5% as long as the difference between banks is not over 4%), as one bank goes over it just gives up and stops any corrections. At this point air to fuel ratio goes out of acceptable range and misfires start.