Hi, I have an issue in my 2013 MB ML350Bluetec (Canada) getting no CEL, but I have sputter/misfire at 1500rpm and it happens sproadically but on every trip. I have had the truck hooked up to a diagnostic and nothing shows as being wrong. Visually all pipes have no rips or holes. I reported a sputter under warranty at startup and dealer did a CDI transmission update. I then had sputter a year later and it was the MAF sensor, but each time I got a CEL, but this time not. I have never run an additive so I just added Stanadyne. Does one tank do enough or should I do many tanks in a row. Or is Lucas Oil additive better as it indicates injector clean as well. It does the misfire even while in park so I've ruled out the transmission. If it is injectors, do I have to replace them all or just the problem ones? If injectors are plugged, would the Lucas Oil be enough to clean them out? My mechanic said fuel pressure was good so wouldn't be fuel filter and thought it might be the throttle sensor. Online reading shows it is possibly a dirty EGR valve or leaking O ring on the intake? I want to attempt to do some of the easier stuff myself and don't just want to start replacing part after part. Any process of elimination I could use? I also haven't been able to find a manual (well one without the rar files). Is anyone else experiencing this symptom and have a suggestion? and/or where to get a service manual? Thanks in advance. Appreciate the help.

 

The only thing that comes to mind is an experience I had with mine, when pulling the upper aluminum pipe that flows forward to the front. I don't know the name for it but I believe it works in junction with the turbo. I had removed it 2 years ago, while changing out my fuel filter. When putting it all back together, the Oring was not fully seated , and each time on acceleration, the engine would give a 'fart' or two! You learn through mistakes, LOL! Anyway, I knew it was something I had tinkered with, so it didn't take me long to find it. NOTE: I saying this all from memory of 2 years ago, and my memory today is about 15 Mins!!!n Good luck...

 

Too much misinformation.

There are two things that you need to keep in mind - there are no codes, and it's a diesel. There are only three things that can lead to a misfire: problems with (a) compression, (b) fuel injector operation, and (c) the fuel itself. It is extremely unlikely that the problem is due to a scored cylinder block, bad piston rings or an issue with the rotating assembly (plus you would have plenty of other signs), so you can pretty much eliminate compression issues - which leaves (b) and (c). I am not sure what fuel you are using, but a relatively cheap test and possibly a fix would be to put a tank of Shell V-Power diesel and give the truck an Italian tune up, i.e. run it hard for the entire tank (either accelerate hard or use the left shift paddle to force it to stay in a lower gear - you want a fair bit of operation in the 3K-4K RPM range). The Shell V-Power diesel has both Cetane improvers and all the detergents you would ever want in a fuel, so it would at the very least eliminate the bad fuel theory, and would furthermore provide all the injector cleaning if that is what they need. If you still have a misfire after you've ran a tank of V-Power diesel, one of your injectors will likely need to be replaced. Yes, they can be replaced individually - you don't have to do all six.

Oil additives can't do anything for a misfire in any engine (except possibly on a two-stroke where the oil gets mixed in with the gas) by definition - the engine oil does not travel through the fuel delivery system. Fuel additives will do various things, but in a diesel where the fuel does a lot more than simply combust - it provides lubrication for the injection system, seals the injection pump and injectors and finally cools the injection system - ANY fuel additive is bound to cause more problems than it solves. I see this over and over again, so forget about diesel additives and cleaners. They will definitely do more damage than good.