Hi everyone. I have a 2007 C-280 4Matic with the 3.0L V6 (my daughter's car). About a month ago she was driving and came to a red light. The engine just shut off and would not restart. I had to towed home and once it was home, I started the engine but it was running extremely rough. I have a Snap-On scanner and pulled the codes and it had the P300 misfire side and the a code for cylinders 4,5,& 6. So I have replaced all of the spark plugs and the coil packs for 4, 5 & 6. After this the misfires became random. It would go to different cylinders every time I would restart the engine. About 2 weeks ago I sent the ECM off to be rebuilt because a MB tech told me that the drivers for the injectors and coils had probably burnt out. I got the ECM back today and installed it. Started up the engine and guess what, Still have the misfires on different cylinders. The first time I started it they were on cylinders 4 & 6. Then they went to 1 & 3. Please help if you can. I can't afford to take it to the dealership so I am having to do this on my own and she needs her car back for collage.

 

I would consider the crank sensor and the multiple cam sensors, the later more likely. Pretty inexpensive parts, easy to DIY install. Check out YouTube for videos .
If the car has high mileage, 100K or more, the timing chain may have stretched and jumped a tooth, maybe 2.

https://www.mbpartscenter.com/?gclid...IaAgptEALw_wcB for parts or FCPeuro.

 

Thanks for the direction. But wouldn't the cam sensors set a code if they were going out?

 

" If the camshaft sensor has failed you will notice some or all of the following:

• Check Engine Light – (CEL) / Service Engine Warning may turn on, and you will have a fault code related to the CAM sensor.
• Intermittent starting – This is a very common problem if the Camshaft Sensor starts to fail. You may notice the car starts fine one day and then hesitates to start the next. It could also be that the car starts fine when cold, but if it warms up, it’s hard to restart it.
• Loss of engine power – Less common but it is possible that the car may hesitate under acceleration or even trigger misfire codes. This is caused because the Electronic Control Module (ECM / ECU) does not receive any information from the CAM sensor, so it doesn’t know the crankshaft position."