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Mercedes-Benz C-Class: Misfire and rough running (C63 4.0 M177 V8, W205)

Misfire and rough running (C63 4.0 M177 V8, W205) is a common engine fault on the Mercedes-Benz C-Class on the 2015–2021 cars, and we rate it major. Putting it right costs $400 to $6,000 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 41 documented faults on the Mercedes-Benz C-Class.

Vehicle
Mercedes-Benz C-Class
Only on
AMG
Engine
4.0L
Years
2015–2021
Fuel
petrol
System
Engine

This page covers the Mercedes-Benz C-Class as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Mercedes-Benz C-Class faults41 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the High-pressure fuel pump or Catalytic converter or Ignition coil yet. We would rather show none than show a picture of a different part.

What goes wrong

The W205 C63 and C63 S with the 4.0 M177 twin turbo V8 have a Mercedes technical bulletin for misfires, rough running and the check engine light. The fixes Mercedes lists, in order, are an engine software update, ignition coils of a newer part number, finding leaks in the turbo intake and intercooler pipes, and then checking for a weak high pressure fuel pump or leaking injectors on one bank. Left alone, misfires can damage the catalytic converters and a leaking injector can wash oil off the cylinder wall.

What you would notice

  • Check engine light on or flashing
  • Shaking or rough idle, worst from cold
  • Hesitation or stutter under boost
  • Engine feels down on power

How to check it

Where to look. Ignition coils and injectors on top of both cylinder banks; turbo intake and intercooler pipes

Start the car from cold if you can and feel for shaking or an uneven idle in the first minute. On the test drive accelerate firmly through the gears and feel for a stutter or hesitation, and watch for a check engine light. Ask whether coils, plugs, injectors or a fuel pump have been replaced and whether the engine software has been updated, and ask for the invoices. If a workshop inspection is possible: have the fault memory read for misfire codes P0300 to P0308 and the misfire counters, and have the intake and boost pipes smoke tested.

Parts involved: High-pressure fuel pump, Catalytic converter, Ignition coil.

What it costs to put right

$400 to $6,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

  • “Has it ever had a misfire or check engine light?”
  • “Have the ignition coils, plugs or injectors been replaced?”
  • “Has the engine software been updated by a Mercedes dealer?”

Now check the Mercedes-Benz C-Class you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

Mercedes-Benz C-Class buyer questions

Is misfire and rough running (c63 4.0 m177 v8, w205) serious on a Mercedes-Benz C-Class?

We rate it major and common on the Mercedes-Benz C-Class. The W205 C63 and C63 S with the 4.0 M177 twin turbo V8 have a Mercedes technical bulletin for misfires, rough running and the check engine light. The fixes Mercedes lists, in order, are an engine software update, ignition coils of a newer part number, finding leaks in the turbo intake and intercooler pipes, and then checking for a weak high pressure fuel pump or leaking injectors on one bank. Left alone, misfires can damage the catalytic converters and a leaking injector can wash oil off the cylinder wall.

How much does it cost to fix on a Mercedes-Benz C-Class?

$400 to $6,000 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Mercedes-Benz C-Class years are affected?

Our research records this fault on the 2015–2021 Mercedes-Benz C-Class. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Start the car from cold if you can and feel for shaking or an uneven idle in the first minute. On the test drive accelerate firmly through the gears and feel for a stutter or hesitation, and watch for a check engine light. Ask whether coils, plugs, injectors or a fuel pump have been replaced and whether the engine software has been updated, and ask for the invoices. If a workshop inspection is possible: have the fault memory read for misfire codes P0300 to P0308 and the misfire counters, and have the intake and boost pipes smoke tested. Look here: Ignition coils and injectors on top of both cylinder banks; turbo intake and intercooler pipes