Rough Idle
Super Member
Joined: Nov 2004
Posts: 992
Likes: 11
From: Illinois
GL550, C55, 335i Coupe, vintage Mustang
Mine is going in on Tuesday after the dealer confirmed my diagnosis with a compression test. The right cylinder head is being replaced. There is a technical bulletin on the issue, but I don't remember which one it is.
Nick
Nick
Newbie
Joined: Jul 2013
Posts: 9
Likes: 0
2008 GL 550
2008 gl550 rough idle
I have a 2008 GL 550. According to computer diagnostic, cylinder 3 misfires.
Very frustrating at stoplights. Seem to still have full power during acceleration though.
Could it be ignition coil?
Very frustrating at stoplights. Seem to still have full power during acceleration though.
Could it be ignition coil?
Junior Member
Joined: Feb 2011
Posts: 20
Likes: 0
From: jacksonville fl
c55 amg gl 450
yes that is the bad coil or spark plug just to make sure take the coil and move it to different spot
MBWorld Fanatic!
Joined: Apr 2003
Posts: 1,464
Likes: 9
From: SoCal OC
S, GL, Escalade ESV, my shoes
Guys, I am a former MB tech(moved on to engineering now at a different company) and this issue is in fact worn valve guides in the head. I have never seen it anywhere but the passenger side head and you may not get codes for it. What the dealer needs to do is run a compression test with their laptop. I have started suffering this same symptom in my GL550 in the last month.
Nick
Nick
Further check showed low compression reading in one of the cylinder (4th one, I think), due to worn out valve guide due to not properly aligned. From the paperwork, look like they changed a bunch of thing & lot of labor.
THe mechanic/advisor didn't seem to be so surprised by what he found, and from his talk, look like he had seen a number of similar problems.
Lucky that car is under warranty (extended warranty from MB), so it cost me nothing. Else it would hurt.
Funny how I was commenting to my wife that we bought the ext warranty for almost a year, and have not used it at all. Two days later, the CEL turned on and car went to dealer for a week.
Last edited by zam2000; Jan 9, 2014 at 02:52 PM.
Member
Joined: Jan 2014
Posts: 247
Likes: 17
From: Chicago, IL
2015 - GL 550
I too faced this problem, rough start and shivery idle with CEL only once, this happened to me after I kept the car in garage without starting it for 4 days (in Last week Cold) took it to the dealer for some other repair and just casually mentioned about this issue, because I never got the same issue after restarting the car until now, after they did some short test and confirmed 2 coils (7 & 8) has gone bad, I was like hummmm 
didn't gave any issue until except once. but I still authorized them to go-ahead and fix it. Anyways car is still with the dealership will see how it goes.
didn't gave any issue until except once. but I still authorized them to go-ahead and fix it. Anyways car is still with the dealership will see how it goes.
MB World Stories
The Best of Mercedes & AMG
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know
Verdad Gallardo
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Junior Member
Joined: Mar 2013
Posts: 16
Likes: 0
2008 C300 4matic sport
I am also having this issue. Slight vibration when in drive and at a complete stop. Goes away once i give it a little gas or put it in neutral.
How do you check the coils without taking the car to the dealer? I changed my plugs 35k miles ago. Should i try new plugs?
2008 C300 4matic sport
90k miles
How do you check the coils without taking the car to the dealer? I changed my plugs 35k miles ago. Should i try new plugs?
2008 C300 4matic sport
90k miles
Junior Member
Joined: Mar 2013
Posts: 16
Likes: 0
2008 C300 4matic sport
I am also having this issue. Slight vibration when in drive and at a complete stop. Goes away once i give it a little gas or put it in neutral.
How do you check the coils without taking the car to the dealer? I changed my plugs 35k miles ago. Should i try new plugs?
2008 C300 4matic sport
90k miles
How do you check the coils without taking the car to the dealer? I changed my plugs 35k miles ago. Should i try new plugs?
2008 C300 4matic sport
90k miles
Member
Joined: Jan 2014
Posts: 247
Likes: 17
From: Chicago, IL
2015 - GL 550
May be you got non-OEM plugs or the plug's are not fit with right torque.
The cheapest way to know the coils bad is take it to any Autozone or AdvanceAutoparts and ask them read the codes from your car they will do it for free, but that doesn't mean you don't have to TIP them please do so....
And also you can download\purchase a app from Googleplay store its called (TORQUE) for $6.00 and buy a bluetooth OBII adapter ($20 I guess) the app will have the list of adapters it work with it and thats it you are good to plug it and and it will read the codes out on your Android....
Hope it helps.
The cheapest way to know the coils bad is take it to any Autozone or AdvanceAutoparts and ask them read the codes from your car they will do it for free, but that doesn't mean you don't have to TIP them please do so....
And also you can download\purchase a app from Googleplay store its called (TORQUE) for $6.00 and buy a bluetooth OBII adapter ($20 I guess) the app will have the list of adapters it work with it and thats it you are good to plug it and and it will read the codes out on your Android....
Hope it helps.
Junior Member
Joined: Mar 2013
Posts: 16
Likes: 0
2008 C300 4matic sport
I have a code reader but my check engine light isn't on. Ill hook my code reader in tonight and see if i get any codes.
I changed my plugs 35,000 miles ago and have not had a problem until now. So i don't think it is that i purchased wrong plugs. I bought OEM plugs.
Ive checked everywhere for vacuum leaks and can't find any.
Changed air filters
Cleaned throttle body
That's why i'm now moving to plugs and wires.
I changed my plugs 35,000 miles ago and have not had a problem until now. So i don't think it is that i purchased wrong plugs. I bought OEM plugs.
Ive checked everywhere for vacuum leaks and can't find any.
Changed air filters
Cleaned throttle body
That's why i'm now moving to plugs and wires.
Junior Member
Joined: Mar 2013
Posts: 16
Likes: 0
2008 C300 4matic sport
Vacuum lines all checked out.
The timing seems fine as this is just an issue at idle in drive. If the timing was messed up i feel that it would be rough all the time.
Coils and plugs are my next move.
If i have a bad coil will i see a code even thought my check engine light isn't on?
THANKS FOR THE HELP
The timing seems fine as this is just an issue at idle in drive. If the timing was messed up i feel that it would be rough all the time.
Coils and plugs are my next move.
If i have a bad coil will i see a code even thought my check engine light isn't on?
THANKS FOR THE HELP
Newbie
Joined: Dec 2020
Posts: 2
Likes: 0
GL450
Mercedes-Benz Class-Action
This is getting out of hand. I spent $12K in repairs in the first 2 months on my used Mercedes when I bought it almost 8 months ago. I bought it so I wouldn’t have any vehicle payments. There’s no way they aren’t in the business of engineering their parts just right to last so so long so you go spend money with them. It’s their greed. This is why they’re killing everyone off with this vaccine. Because they’ve gotten too greedy and now we’re starting to make out that they are responsible for the child sex trafficking. I’ve babied mine and take very good care of it and now I have this whining sound. I’m done letting these corporate piece of s***s not take accountability for their problems. Saying “it’s normal”.
This ends now. What can we do? And don’t say nothing you can do, because there is something we can do. I’ve had enough of this. I thought I was buying a nice reliable vehicle only to learn that this would be the BIGGEST piece of junk I ever spent money on in my life.
This ends now. What can we do? And don’t say nothing you can do, because there is something we can do. I’ve had enough of this. I thought I was buying a nice reliable vehicle only to learn that this would be the BIGGEST piece of junk I ever spent money on in my life.
Last edited by Anthony Ochs; Jul 8, 2021 at 11:58 PM.
Newbie
Joined: Oct 2021
Posts: 6
Likes: 6
GL550
This is getting out of hand. I spent $12K in repairs in the first 2 months on my used Mercedes when I bought it almost 8 months ago. I bought it so I wouldn’t have any vehicle payments. There’s no way they aren’t in the business of engineering their parts just right to last so so long so you go spend money with them. It’s their greed. This is why they’re killing everyone off with this vaccine. Because they’ve gotten too greedy and now we’re starting to make out that they are responsible for the child sex trafficking. I’ve babied mine and take very good care of it and now I have this whining sound. I’m done letting these corporate piece of s***s not take accountability for their problems. Saying “it’s normal”.
This ends now. What can we do? And don’t say nothing you can do, because there is something we can do. I’ve had enough of this. I thought I was buying a nice reliable vehicle only to learn that this would be the BIGGEST piece of junk I ever spent money on in my life.
This ends now. What can we do? And don’t say nothing you can do, because there is something we can do. I’ve had enough of this. I thought I was buying a nice reliable vehicle only to learn that this would be the BIGGEST piece of junk I ever spent money on in my life.
