milan25

I have 40k miles, Dp and tune, i put some fuel system cleaner this fill up. Could that be the cause?

munis

Mercedes specially warns about using any kind of fuel system cleaner in the manual. Why did you do it again? Just curious.

milan25

Just to "clean" the injectors and fuel system a bit

munis

How did you know they were dirty? Did you take gas from a bad pump? Premium gas most of the time will never foul up your fuel system if you get them from any of the top tiered pumps.

milan25

Chevron Techron is one of the MB approved fuel cleaners btw

milan25

just to keep them maintained

munis

Well I am sure the manual said not to use any. Anyhoo, my suggestion would be to slowly drive and empty this tank. And then get a clean tank of good gas in, and hammer the car. Like absolutely hammer the **** out it. Do multiple 0 to 200kmph runs if possible. Should resolve itself.

right_mr

if your tune is one that can be easily unplugged then do that for now.while you empty the tank out

milan25

Should i try putting a gallon or 2 of E85?

AlexZTuned

munis

That is why I suggested emptying the current tank by driving slowly first. But your way is better. My suggestion to hammer the car was after you are certain you have clean fuel in the car.

skim7x

What tune do you have and when was it tuned?

milan25

I have a dyno tune from a local shop and have had it for a year and about 17k miles

milan25

Could it be spark plugs or the Ignition Coils? Haven't changed plugs yet and the dealership said they fixed the coil recall, but I don't go to that dealer anymore. They are pretty bad. So again could it be the coils

C63SVERT

no thats not going to fix that. and as a general rule, dont put E85 in anything that isnt tuned for it. it sounds like its got a fouled plug or a bad coil. but in my 2015 E63, it would have a flashing CEL and would run like **** when it would burn up a plug.

munis

It can be the coils. I have seen coil packs getting busted for tuned cars a lot more often than the stock cars. EC told me the same thing. But you will get misfiring codes 99 percent of the time if that was the case. I would put clean gas in first and driving first before you troubleshoot it further.

milan25

I really appreciate all your help guys. I'll wait and see i guess. Hope it fixes itself.

C63SVERT

dude its not going to fix itself. id run the gas down, fill it up, then disconnect the battery, reset the parameters in the ECU, if it keeps doing it, throw a set of plugs in it.

munis

Disconnecting the battery resets the ECU? I heard it doesn't for these newer cars as they have an auxilary battery for back up. You need Xentry to reset adaptations.

C63SVERT

you may be right. i haven't had to do it on any of my Mercedes. I'm only used to having to do it in any of my past american cars. im also not sure how similar the systems are in your C43 vs a C63.

munis

There aren't a lot of similarities. But certain things may be common to platforms. I am not sure either, so do not take my word for it. I had some rough shifting problems after an accident. I know for sure that disconnecting the battery, did not reset any of my adaptations. A Xentry TCU reset fixed the problem for me and the tech told me these new cars have an auxiliary battery, so just simply disconnecting the battery would not help reset adaptations.

milan25

Sorry for a late update, but Cylinder 5 spark plug went out. When is everyone changing their spark plugs? I have 41k miles with stage 2 haven't changed them yet.

Fame Douglas

AlexZTuned

Probably means the plug fouled out from running rich.

milan25

The dealer replaced under warranty, and they said the ceramic part of the spark plug was cracked