Misfires at HPDE P0300, P0306, P0307

Jun 15, 2022 | 12:03 AM

Spazdoc

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Joined: Dec 2010

Posts: 306

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From: Earth

C63S, 2004 S4, 2001 S4 Avant

Misfires at HPDE P0300, P0306, P0307

As background, I have modal intake and modal catted DP (200 CPSI), and NO tune. I did one track day in 2020, 4 track days in 2021. In all those prior sessions, I never had a misfire, and the only CEL was a P0420 after a couple sessions and permanently over the winter because a spacer expired. Replaced the spacer, P0420 went away. Thanks for response, will send to dealer.

Last edited by Spazdoc; Jun 28, 2022 at 10:10 AM. Reason: Typo correction

Jun 15, 2022 | 10:06 PM

NYCSoiL

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Joined: Apr 2016

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From: Brooklyn, NY

2018 GT R; G82; M340

Jun 30, 2022 | 03:26 PM

Spazdoc

Thread Starter

Senior Member

Joined: Dec 2010

Posts: 306

Likes: 27

From: Earth

C63S, 2004 S4, 2001 S4 Avant

I have a 2020 C63S, but an early build. I am wondering if I can check if I have new or old ignition coils.

Also, is there a TSB or other ID# for that bulletin?

Jun 30, 2022 | 08:58 PM

MaxVO2

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Joined: Dec 2021

Posts: 268

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From: Maryland

2018 C63s

Quote:

Originally Posted by Spazdoc

I have a 2020 C63S, but an early build. I am wondering if I can check if I have new or old ignition coils.

Also, is there a TSB or other ID# for that bulletin?

*****I have aftermarket intakes on my car now, but I think you can see at least one or two of the ignition coils even with the stock air cleaner on, and check the part # on the coils. I have a 2018 C63s but have the updated coils. Pic below of my motor during my turbo swap last week, passenger side - I have circled two of the coils (car has 4), and even though the pic is not clear - the part #'s are visible on the top surface of the coils. You *might* need to move an airbox a bit out of the way perhaps to see, but this is very easy to do.

The newer coils came with my car, but I am the 2md owner so think the original owner had the new coils put in.

Jun 30, 2022 | 09:01 PM

Spazdoc

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Joined: Dec 2010

Posts: 306

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From: Earth

C63S, 2004 S4, 2001 S4 Avant

Well great. Just got a text from the SA. Dropped off the car Tuesday morning, they just looked at it 2 days later, and said that because of the non-OEM downpipes and intake, they cannot diagnose the misfires. The is no active CEL for catalytic converter (self cleared), and have not had a single misfire in the prior 18 months and 4 track days with the same set up. Just frustrated, especially coming from a previous BMW with modifications, and the SA would go to bat for you (even though I did not buy the car from the dealership). And to think I put on DP just because MB nerfed the C63 exhaust.

Looks like I am putting back the OEM cats and intake.

Jul 3, 2022 | 12:16 AM

Manucanada

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Joined: Jul 2022

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W221 S550

W221 S550

Hey guys I have a misfire on cylinders 1-3-4 I already changed all the spark plugs and those 3 ignition coils but I still have the issue.
Also I have a lot of white smoke when I just start the car... help please

Mar 15, 2026 | 02:39 PM

Slawand88

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Joined: Sep 2025

Posts: 16

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2018 AMG GTR

Quote:

Originally Posted by NYCSoiL

I am trying to find an official version of this. Like a TSB or identification number, but I am having trouble doing so. My car is eligible, but I need to track down this publication so that Mercedes can cover it. Please advise.