Your diagram will show small "Teflon" rings and plastic arms. These break. You don't need a $1,200 new manifold; you can buy a repair kit (L shaped levers) for $30 if you know which part to search for.
While the M272 is known for its smooth power delivery, it is also famous for a few critical failure points (looking at you, balance shaft sprocket). Whether you are troubleshooting a rough idle, rebuilding a top end, or just trying to understand where that oil leak is coming from,
Disclaimer: Always verify part numbers for your specific VIN. Mercedes changed designs constantly mid-production.
If your diagram shows the intermediate shaft gear (part #272 030 03 01), take note. If the engine serial number is lower than #2729..30 088933, that gear is likely soft and failing. The fix requires removing the transmission, oil pan, and timing cover—a $3,000+ job.