Why does my spark plugs always becames dark and i need to like clean it once a week

Asked by Feb 18, 2016 at 11:57 AM about the 2003 Mercedes-Benz C-Class

Question type: Maintenance & Repair

My spark plugs always becomes black/dark like missfire but anyone who
know why it becomes like this and how can i fix that please help me

3 Answers

65,535

Should get it to a shop. The plugs are black because it is running rich. There must be a bad 02 sensor, or some other sensor causing this. A shop can diagnose this.

1 out of 1 people think this is helpful.
232,615

Yes, and most probably a Service or check engine light on too?

Engine light is not on

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