FLBenz

Took my car in for its first service at 9,800 miles. I noticed a couple of months ago that it seems to be idling rough. The dealer at first said yes they agree. Now they are telling me its normal. They say they have compared it to another model just like it and it idles the same way. I know this started a couple of months ago and I was waiting for the service notification to pop up so they could do the service and fix the idle at the same time. Anyone else have this issue?

digitalnav

Would help if you had video

auditoamg

+1

MarkC63

I have had issues at idle. Revs fluctuate up and down like the car is about to stall. They did a software update back in February which gave have me the engine and transmission update to increase exhaust pops and bangs. That seemed to fix it for a while, but now it's back. A couple of times the check engine light starting flashing and then went solid. If I turn the car off and back on again, engine light is cleared and car is running fine. I also had it so bad the other week the car started to misfire. Took it into Mercedes straight away and they replaced the ignition coils. It was fine again for a few days, but the problem came back and now the check engine light is on so going back into Mercedes for round 4! Feels to me like an electrical or sensor issue because it is fixed by turning the car off and on again. It also only happens when the car is up to temperature and when stationary (at idle). It also doesn't happen all the time. Let's hope they can sort it this time round! I will keep you posted. Car is going in next week.

Rorie

Took my car into the shop for a B1. I am in Canada. They told me at the same time they have a recall on the ignition coil. I will let you know how the car feels when I get it back.

R

Yandoodle

DRGG

I just had my 1875 mile rear differential fluid replacement on my 2018 C63s coupe. While there, I decided to have an oil change, too. Afterwards it idled very roughly. To make a long story short, they drained the oil and refilled to the proper level and the rough idle disappeared. I hope this helps others with a similar issue. I Googled this problem and got several hits with respect to rough idle and oil over-fill. It was resolved quickly in this case. Service personnel seemed to be a bit baffled in the beginning, so I guess it's not an everyday problem.

MarkC63

I took mine back to Mercedes after they had replaced the coils because I was still getting the rough idle and misfire engine codes. They switched the new coils they had previously installed round to see if the problem would follow what the computer was reporting the misfiring cylinder.
After that it misfired again and I was starting to get frustrated! Then a mate suggested I may have had some crap fuel at some point and suggested some fuel additive to clean out the injectors etc etc. It worked! It's been 9 months now and it hasn't skipped a beat (misfire or rough idle). Simple solution at the end of the day!

layzie12g

I have had to do an injector in a G wagon with that engine before. It was in multiple times for ignition related things, but it was a bad injector causing the issue.