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oskarfox8

Mercedes SL running lean

My 2021 Mercedes SL gasoline engine is running too lean Could a faulty mass air flow sensor cause this

Summary of the thread

A 2021 Mercedes SL is experiencing a lean running condition, potentially caused by a faulty mass air flow sensor. However, after scanning the ECU, codes indicate a lean mixture on both banks, suggesting a fuel delivery issue. The problem was confirmed to be a defective fuel injector, which was resolved by replacing the injector and updating the ECU software.

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4 comment(s)

matteomayer1

A lean running condition can be frustrating The symptoms you describe, particularly the jerking under acceleration, are highly indicative of a fuel delivery issue Considering the vehicle's mileage and the consistent nature of the problem, I would consider the possibility of a defective injection valve or injector I encountered a similar issue with my previous BMW although that was a diesel model Have you scanned the ECU for diagnostic trouble codes

oskarfox8 (community.author)

I did scan the ECU and it's throwing codes related to a lean mixture on both banks That's what initially led me to suspect the fuel injectors You mentioned you had a similar issue, but with a diesel Was it also injector related and what was your solution

matteomayer1

In my case, the diagnostic codes also pointed to a lean mixture The root cause was a malfunctioning fuel injector Given the error codes and your symptoms, it is highly probable that one or more of your fuel injectors are not functioning optimally It would be prudent to consult with a qualified technician for diagnosis and repair Attempting a repair without proper diagnostic tools and expertise could potentially exacerbate the issue or damage other components such as the intake manifold For information purposes, the repair cost on my diesel was in a similar ballpark

oskarfox8 (community.author)

Thanks for the insight I took it to a trusted workshop, and after thorough testing, they confirmed it was indeed a defective fuel injector Replacing the faulty injector and a software to the ECU cost me 515€ Runs like new again

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MERCEDES

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SL