Some things to check

Fuel pressure regulators leak on these and M104 engines, could be a rich misfire as the vacuum source is the left bank (5-8)

Do a compression test?

What are the actual misfire counts? The HFM-SFI stops monitoring misfire counts once the throttle is moved from the idle position. Then you need to read "smooth running" values.

I would say the cat could be an issue as the W210's with the M119's had a similar issue, but they also had low power when hot. I assume powers good? Easy enough to loosen the 4 bolts to see if there is a difference.

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