amir1

I am experiencing a lot of misfires on the V12 engine of my S65 Coupe. No check engine light yet, but i'm sure as it gets worse, it will appear. I know Mercedes has had issues with coil packs. I had the same issue on my other v12 Maybach and on my S560. Anyone else experiencing misfires? (engine every now and then runs rough for a second or two. You can easily see the rpm gage needle drop, then stabilize after a few seconds)

haa

I see the same thing since day 1 of owning my S65 Cabriolet especially after cold start. No check engine light ever. have around 9000 miles on it

vettebk

My 2007 TT V12 misses intermittently also. It happens mostly on my left side cylenders 7-12 and sets a P0300 P0312 and sometimes a P1170. I can clear the codes and she is fine for a few weeks. Then it comes back. I switched to V12icpack.com coil packs on the left side and I also replaced the voltage transformer with one of theirs. And I run a container of Techron fuel injector cleaner about six times a year. Mostly, my misses have gone. It still happens on gasoline less than 93 octane once in awhile and usually when I am heavy on the throttle.

How many miles on your plugs and coil packs?

Viper98912

I thought the coil pack issues were mostly on the M275 (older) engines, whereas the newer M279 went to individual coils?

vettebk

Absolutely right. My engine is a M275 V12 TT with two coil packs - one on each bank. The newer engines use individual coils. Better design.

amir1

My Car has around 8,000 miles on it. They already replaced two coil packs. But there are probably more that should be replaced. It's not my DD, so I need to find time to take it in. Once they figure it out i'll report further. Thanks for the help.

Viper98912

If you can't get it figured out, please let me know as I guess I'll have to buy your S65 Coupe from you. At a discount of course, since it's broken.

amir1

My BABY ain't for sale. LOL As to the bad coil packs, I might have to pressure the dealer to replace all of them to prevent this problem from recurring. They sort of hinted that they will agree to it if the problem persists. I'm taking a wait and see approach for now.

Jehude

Great members of this forum,
I just joined and I can say I’ve received valuable information from here than anywhere else. I have a 2012 S600 with 80k miles on the clock. The big girl started misfiring on 1,7 and 9 cylinders
I have fairly adequate mechanic skills and enough tools to change out the 24 plugs but am a bit scared of cracking the delicate coil pack.
So my questions are:

A. Is the misfiring only from the plugs?

B. Should I take it to a shop, give them the plugs to install for me?

Your advice and encouragement would be greatly appreciated.

Jehude

MBS63AMG

My 2017 S63 misfired at 70K miles. Luckily I was only a mile from the dealership and they said they couldn't find a problem. I too had just got on the throttle a little heavy and it happened. I no longer have this car but it was fun to drive.