Ongoing Misfire + Power Loss on 2020 Mercedes E220d (OM654) — Anyone Faced This?

[akhera1]

Hi everyone,


I’ve been battling a frustrating and unresolved issue with my 2020 Mercedes E-Class 220d Coupe (OM654 engine) for months now, and I’m really hoping someone else has experienced something similar.





Symptoms:

• Cold start misfire and judder that lasts 1–2 minutes, then settles down
• Occasional loss of acceleration after driving for ~30–40+ minutes
• No dashboard warning lights
• No stored fault codes after diagnostics (aside from a P0101 months ago)
• Fan sometimes stays on after shutoff (rare — once every 6–8 weeks)

Timeline of events:

• March: Took it to a Mercedes specialist due to one-off misfire and fan staying on. No codes, but they changed fuel filters and air filter.
• Next day: Power loss issue appeared — would take longer to reach speed after driving for 30+ mins. No codes.
• April: Got a P0101 code. Cleaned and later replaced the MAF sensor.
• After MAF change: Cold start misfire began, and it has now become consistent.
• May: Had a full A5 + gearbox service done and replaced the MAF at the same specialist. Misfire got worse. No codes.
• June: Took it to another Mercedes specialist. They ran smooth running and cold start tests — still no codes but confirmed the misfire.
• Took it to a third garage (well-reviewed local) and now they believe the issue is mechanical, not airflow/sensor related. Their diagnosis is worn tappets (lifters) and rocker arms — possibly even the camshaft.

Other notes:

• No coolant loss (rules out EGR cooler leak)
• MAF is new and OEM
• Fuel filter change seemed to be the moment power delivery changed
• Misfire began immediately after MAF was changed
• Garage says the lifters may be bleeding down overnight, causing rough valve operation on startup

Has anyone else with the OM654 engine (or similar diesel Merc) experienced something like this? I’ve been chasing EGR, injectors, glow plugs, and sensors — and now suddenly it’s a top-end mechanical issue?





Would really appreciate any input before I authorise a major repair.





Thanks in advance.

 

[akhera1]

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- this is a video of the engine shaking on start

 

[akhera1]

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This is a video of the engine on cold start

 

[ernie]

You don't mention the car's mileage, but valve and camshaft troubles have been reported on these engines. It might be worth a search on YouTube.

Ernie

 

[Jobsworth]

Difficult to tell from video, but sounds like worn camshaft rockers to me. Very common on this engine. “Plopping” sound in air filter box on tickover is dead giveaway

 

[akhera1]

You don't mention the car's mileage, but valve and camshaft troubles have been reported on these engines. It might be worth a search on YouTube.

Ernie

Hi, thanks for the reply mileage is 99k

 

[akhera1]

Difficult to tell from video, but sounds like worn camshaft rockers to me. Very common on this engine. “Plopping” sound in air filter box on tickover is dead giveaway

Thanks for getting back to me, appreciate you taking the time

 

[Jobsworth]

Mileage is right for rockers imho