12/03/2026
Mercedes A35 AMG, in for rough idle and underpowered.
Diagnostics revealed misfire cylinder four.
Checked the service interval of the spark plugs, which is 45,000miles or 36 months.
Our car has 55,000miles and is 60 months old. Had a look through the service history, no sign of plugs being done. An oil and filter only change had been done at 43,000 miles, suggesting that the plugs were not done on time.
The plugs are buried on these cars and require a bit of work to access them. Once we got them out it was very apparent they had never been changed, Mercedes branded plugs and filthy. On one plug the gap was being bridged by crusty horrible stuff. (Pictured).
New plugs fitted, test driven and misfire had disappeared.
01360 302 332
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