New W205 Issue, Check Engine Light, Rough Idle and Accel

Sep 11, 2018 | 06:15 AM

Nate0525

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Newbie

Joined: Sep 2018

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Black W205 Base 4Matic, Premium 2 Package

New W205 Issue, Check Engine Light, Rough Idle and Accel

About a week ago my 2015 w205 C300 had a slight jerk every once in a while while idling. Dismissed it for a few days as bad gas but it progressively got worse. Now the check engine light is on and under any acceleration past 3000rpm the car will hesitate and stutter. Overall I’ve been very disappointed in the build quality of this vehicle, coming from a w204. I am out of warranty on this car and really hope this is a MAF sensor or something cheap. I’ll update everyone when I go to the dealer today.

Sep 11, 2018 | 01:22 PM

DoorHandle_LED

Member

Joined: Jan 2018

Posts: 153

Likes: 33

2015 C 300 4MATIC

Could you possibly get the check engine code and let us know the solution. This might be helpful to folks in the future. Hoping things working out for you and it's a simple repair.

Sep 11, 2018 | 08:11 PM

Cali4niadriver

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Joined: Feb 2018

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W205

Same thing happened to me, initially was a spark plug issue but long story short ended up replacing the engine with a new one under warranty.

Sep 12, 2018 | 04:43 PM

Nate0525

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Black W205 Base 4Matic, Premium 2 Package

UPDATE

Dealer diagnosed problem as a bad fuel injector and also recommended replacing all of the spark plugs. The error code causing the misfire was a misfire on cylinder 1. Dealer quoted me $1300 for parts and labor. That’s redicluous. I’m going to buy these parts and do it myself. Anything I need to know? Spark plugs I can do easily but I really don’t know anything about replacing the injector. Any direction would be appreciated.

Sep 13, 2018 | 03:44 AM

guhvies

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Joined: Feb 2006

Posts: 798

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From: Bromley, UK

2017 C43 AMG Saloon

If you're out of the warranty period I think you should start looking for a good indie. They'll be a lot cheaper hopefully and still do an excellent job.

Sep 13, 2018 | 04:03 AM

Nate0525

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Black W205 Base 4Matic, Premium 2 Package

Quote:

Originally Posted by guhvies

If you're out of the warranty period I think you should start looking for a good indie. They'll be a lot cheaper hopefully and still do an excellent job.

I’m going to attempt to do it myself. The spark plugs are cheap and easy. I have the WIS software from Mercedes and I’ve been looking at the process for replacing the fuel injector, it seems simple enough. I’ll do these repairs myself and I’ll update how it went. Just waiting on parts now.

Sep 23, 2018 | 03:42 AM

Nate0525

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Black W205 Base 4Matic, Premium 2 Package

UPDATE CAR FIXED!

After changing the spark plugs and coils myself the car runs like a dream. I’m thinking the coils may have been a little much but I did them anyway. The car runs like new and after clearing the codes, everything is perfect. The spark plugs where absolutely horrendous. Spark plugs had 55k miles on them.

Last edited by Nate0525; Sep 23, 2018 at 03:45 AM.

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Jul 18, 2019 | 05:22 PM

DadMerc

Newbie

Joined: Jul 2019

Posts: 2

Likes: 0

2015 C300 Sport W205

Quote:

Originally Posted by Cali4niadriver

Same thing happened to me, initially was a spark plug issue but long story short ended up replacing the engine with a new one under warranty.

Hey @Cali4niadriver - I ran into the same issue recently with my '15 C300. Dealer is replacing the engine under warranty but found the root cause to be bits of the spark plug in one of the cylinders - stating the spark plug failed and scored the inside of the cylinder.

Did your dealer share the root cause of your issue?