Can faulty spark plugs cause poor fuel economy and engine performance in my Mercedes-Benz E-Class?

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Can faulty spark plugs cause poor fuel economy and engine performance in my Mercedes-Benz E-Class?

Lately, I’ve noticed a in fuel efficiency and a lack of smooth acceleration in my E-Class. Could faulty o r dirty spark plugs be the reason? How exactly do spark plug problems affect engine performance and mileage in these cars?

Talha Kyanii asked on 11 Oct 2025 13:47:10 pm

1 Answer

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Gari Master - on 11 Oct 2025 13:47:58 pm

Yes, faulty o r worn spark plugs can directly affect both fuel economy and engine performance. Here’s how:

Incomplete Combustion: Bad spark plugs dont ignite the air-fuel mixture efficiently, wasting fuel.

Increased Fuel Consumption: The engine compensates for poor combustion by injecting more fuel, reducing mileage.

Loss of Acceleration Power: Faulty spark plugs can cause hesitation and sluggish acceleration.

Engine Knocking o r Ping: Incorrect spark timing due to bad plugs can cause knocking, especially on lower-quality fuel.

What to Do:
If youre experiencing low mileage, poor pickup, o r engine knocking, inspect and replace the spark plugs. Also ensure your fuel and air filters are clean, and that the engine is tuned properly.