When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I was driving in sport plus and i downshifted from 3rd to 2nd it let out a loud pop from exhaust (little louder than usual) didn't think nothing of it because it sometimes does that because of the catless downpipe but this time the car stopped pushing power after..
it made the car misfire so it went into limp mode with my check engine light flickering
The car is also making weird popping noises when i drive really slow under 15 mph
For starters get your intake fixed. It says it's leaking. That will throw off your air/fuel mixture as unmetered air gets into the engine. That's probably the most likely cause, since several of your cylinders have misfires. FWIW, there's also an ECU update for the 2019 related to misfires. I had a misfire on one cylinder after a canyon run in Race mode. They swapped two of the coils and updated the ECU. It hasn't returned since. Other options are bad spark plugs or bad coils. What's the mileage on this? Have you had your spark plugs replaced yet at 5 year/50k miles, whichever comes first?
Last edited by superswiss; Oct 2, 2025 at 12:56 PM.
Well, the engine isn't running properly with an intake leak, regardless on which side it is. History on this car would be interesting to see as well. Any engine problems in the past? Do you know when the spark plugs got replaced by the previous owner?
The intake leak i don't think should cause a misfire on 4 cylinders ( I swapped it back to the original intakes to see if it would fix the misfire but it didn't )
I don't know when the spark plugs were replaced
The car had a fuel pump issue which got fixed at Mercedes a month ago
I was driving in sport plus and i downshifted from 3rd to 2nd it let out a loud pop from exhaust (little louder than usual) didn't think nothing of it because it sometimes does that because of the catless downpipe but this time the car stopped pushing power after..
it made the car misfire so it went into limp mode with my check engine light flickering
The car is also making weird popping noises when i drive really slow under 15 mph
RPM's struggle while idling as well
Anyone know what could be the issue??
I also have a 2019 C63s coupe and few years ago had #5 and # 6 misfire.
The MB Dealership determined it was the ignition coils.
Note the attachment. If it determined it is the Ignition Coils it will be covered under warrant till year 2034 or 150,000 miles.
For starters get your intake fixed. It says it's leaking. That will throw off your air/fuel mixture as unmetered air gets into the engine. That's probably the most likely cause, since several of your cylinders have misfires. FWIW, there's also an ECU update for the 2019 related to misfires. I had a misfire on one cylinder after a canyon run in Race mode. They swapped two of the coils and updated the ECU. It hasn't returned since. Other options are bad spark plugs or bad coils. What's the mileage on this? Have you had your spark plugs replaced yet at 5 year/50k miles, whichever comes first?
You mention a ECU update for 2019 models, any way to find what version the updated one is and how to check it?
I had someone come out and do a smoke test since that's what everyone recommended me to start off with, the guy did a smoke test only on the left turbo inlet and nothing happened for 10minutes till we started seeing smoke coming from underneath the car we looked & looked nothing, till he was inspecting further on the driver side of the vehicle.
We noticed the Intake Manifold on the driver side was split open i'm just a little confused because misfires are on the passenger side of the car but we noticed intake manifold split open on the driver side,
Is this the cause to my misfire?
& I found 2 intake manifolds on ebay not too sure if its the right fitment for my car though any help? Part number is different but shows the same year & model.
Hard to tell from the picture, but it looks like the normal plastic welding on the intake manifold. Usually, when you smoke-test these engines, if the intake has split open, you’ll see smoke fairly quickly (within 2–3 minutes). I’ve also seen smoke coming from the rear main seal area, it can escape from the top of the bell housing and follow the engine, exiting under the hood on the driver’s side. Both oil separator are a weak point on these engine, causing rear main seal to failed.
Since your misfire is happening on bank 1, I would focus on that side first before checking the other bank. With Xentry or an aftermarket scanner, you can check the fault counter to identify which cylinder is misfiring.
I’d start by swapping the ignition coils from a known good cylinder and replacing all the spark plugs as maintenance, then retesting. These engines are also prone to bad injectors, which can leak into the cylinder and cause misfires. A borescope inspection right after cranking the engine (to build fuel pressure) can easily reveal a leaking injector.
You can also warm up the engine to operating temperature, shut it off, and monitor the fuel rail pressure on both banks. Normally, after shutdown, the pressure will rise slowly. If one bank’s pressure drops or fails to rise, that indicates a leaking fuel injector.
If you’re looking for OEM injectors, I sell them for a fraction of the dealer’s price.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
