W204 C63 revs fluctuate at low rpm, possible misfire

Oct 17, 2023 | 03:26 AM

Baretto

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W204 AMG C63

W204 C63 revs fluctuate at low rpm, possible misfire

Hi

I wonder if someone can help me with a problem that is driving me crazy with my 2012 C63.

Between 1k-2k rpm at low speeds, the revs fluctuate up and down, almost like a misfire, although I'm not sure if it is a misfire.

The problem isn't noticeable past 2k rpm. If I am in a low gear and accelerate slowly the problem doesn't happen, it only seems to happen if I am between 1k rpm and 2k rpm in 3rd gear and above.

Things to note are:

All injectors were replaced 1000 miles ago, but the problem was appearing before that.
The spark plugs were replaced on last years service 10k miles ago
I have performed a TCU reset and that made no difference
The last gearbox service was 40k miles ago

I had the car in for a service at MB a few days ago and they noticed the problem and plugged it in. There are no codes showing and they said all plugs seem to be working. The technician said his gut feeling is that is an engine problem, which has got me quite worried.

The car has 80,000 miles on the clock and full MB service history.

Has anybody else experienced this before? Misfires at low rpm, bouncing revs, but no codes thrown?

Thanks in advance.