Wk statesman ls1 mis fire o2 s replaced

[Spannaman]

Hi guys, looking for answers about my mis fire problem, just a run down on my engine, it's stock has lots of new parts , I've have a mis and trying to get information to fix it , I've replaced coils, leads , plugs , coil harnesses on both sides , but still has this mis problem, been to mechanics, had computer hocked up n still have this problem, .
Can anyone shed some light on this for me . Cheers

 

[harrop.senator]

Done a compression test? Might be a mechanical miss and valve related.

Is it using any coolant? Water in the cylinders makes a misfire too.