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2006 S500 4matic, 2008 S550 4matic
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232 Posts
Discussion Starter #1 (Edited)
I got the codes:
0640 - misfiring of cylinder 5 (P0305)
0660 - misfiring of cylinder 7 (P0307)
0632 misfiring (P0300)
May I assume that changing plugs and coils will fix the problem? The car when I bought it had 140 000 Miles and I am not sure if they changed plugs at all? I guess I need to change all 8 plugs (are there 8 of the on the car - S550 2008 4matic?)
If coils are working do I still need to change them? I understand that I need to change all plugs but may get away with changing one or two coils if they fail?

What is the best plugs for this car? FCP Euro offer bosch - do I stick to it?
 

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Registered
2006 S500 4matic, 2008 S550 4matic
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232 Posts
Discussion Starter #2
Looking at several videos on youtube decided that I can change plugs and coils myself - it seems very easy. I guess the main challenge not to snap plugs while removing and apply proper tork putting them back? I also came to a conclusion that while I need to change all plugs which should improve my engine performance I do not have to change coils unless they malfunction. Is it correct? Is it true that coils don't deteriorate but either work or not? And one more: can misfire be related to something beside coil and spark plugs?
 

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Premium Member
2007 S550
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9 Posts
I got the codes:
0640 - misfiring of cylinder 5 (P0305)
0660 - misfiring of cylinder 7 (P0307)
0632 misfiring (P0300)
May I assume that changing plugs and coils will fix the problem? The car when I bought it had 140 000 Miles and I am not sure if they changed plugs at all? I guess I need to change all 8 plugs (are there 8 of the on the car - S550 2008 4matic?)
If coils are working do I still need to change them? I understand that I need to change all plugs but may get away with changing one or two coils if they fail?

What is the best plugs for this car? FCP Euro offer bosch - do I stick to it?
I would check the fuel injectors. Do a switch to see if the code shows up for a different cyl. I had some code problems, it wasn't the ignition coils or the plugs which i needed to have changed when I bought my 2007 S550 with 88,000. But that didn't solve the problem. Finally, My friends at Miami Motoring LLC found the problem. Why?, because they are automotive geniuses. Anyone living in South Florida needs to use Miami Motoring!
 

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2006 S500 4matic, 2008 S550 4matic
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232 Posts
Discussion Starter #5
Thank you all for advice. Today I changed 4 plugs (all on the driver side). The reason to do this side first was that misfire was in cylinders 5 and 7. I also swapped coils 5 to 6 cylinder and 7 to 8 cylinder. First I noted that it rough idle is gone. I also do not feel jerks as I felt before typical for misfire, however I got new issue: it feels that at certain speeds it looses acceleration. I experienced it on the way to a gas station but on the way back everything was good. Is it possible that the whole thing with misfiring was related to poor gas? And another question about coils. May I say that when a coil fails it fails completely and does not make spark to the cylinder which it serves at all or it still may give a spark every second time and cause jerks similar as sparks can do?

I am new with it and it is my second time in my life changing the sparks so any advice or suggestions will be very useful.
 

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Premium Member
2007 S550
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9 Posts
Thank you all for advice. Today I changed 4 plugs (all on the driver side). The reason to do this side first was that misfire was in cylinders 5 and 7. I also swapped coils 5 to 6 cylinder and 7 to 8 cylinder. First I noted that it rough idle is gone. I also do not feel jerks as I felt before typical for misfire, however I got new issue: it feels that at certain speeds it looses acceleration. I experienced it on the way to a gas station but on the way back everything was good. Is it possible that the whole thing with misfiring was related to poor gas? And another question about coils. May I say that when a coil fails it fails completely and does not make spark to the cylinder which it serves at all or it still may give a spark every second time and cause jerks similar as sparks can do?

I am new with it and it is my second time in my life changing the sparks so any advice or suggestions will be very useful.
Good Morning;
I believe the gentlemen are from Belarus, a satellite of Russia unfortunately. Send them an E mail to [email protected]
I would love to start a TV show similar to Wheeler Dealers only more down and dirty. They just took in a Porsche that's worth $40K for $17K that has been salvaged. They will fix this up to perfect condition and sell it on E Bay. All customers are satisfied. I stopped in yesterday and listening to these wholesalers wanting repair prices before even looking at the vehicle was hysterical.
 

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I have an S600 and noticed a tremendous improvement in acceleration and smoothness by changing the coil packs. If you have over 100k on the car, I would consider it normal maintenance.
 

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2006 S500 4matic, 2008 S550 4matic
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232 Posts
Discussion Starter #8
My understanding is that coils can not degrade over time contrary to spark plugs. Coils are like light bulb - either work or not, while plugs are like brakes - can wear out over time. Am I correct of that?

Also - my current understanding is that there are only three things which can cause misfiring: plugs, coils and clogged injectors - is it true?
 
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