I have a 2020 Mercedes A220 that has a misfire in the #4 Cylinder. I replaced the spark plug and ignition coil. This lasted about 3 weeks, then the code reappeared. When the code showed back up I replaced the spark plug again and replaced all 4 along with all 4 ignition coils. The code will not go away and the engine will still idle rough and lose power while driving. Is there an issue that i am missing or a solution to fix this problem?

Sounds like internal mechanical issue. Pull valve cover and inspect valve valve train. How may miles are on it? May be worn valve guides.

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Jim

It has roughly 60K on it. I can dig a little deeper into the engine and and take a look at the valves.

check specifically for carbon buildup on the valves. I assume the a220 is a DI engine...60k would be low for that but definitely not unheard of (esp if fuel quality is low).

How did the spark plugs look? could also be an injector.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

Do a compression test before you tear it apart....

Spark plugs were slightly burnt up on the first change. Carbon on each. Fuel has always been 91 since it was purchased. Can't guarantee quality of it though. I will check the injectors along with the carbon build up.

Oh yea as stated do compression test first.

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Jim