Mercedes B Klasse Cold Start Issue

A rough idle on a cold start sounds familiar I own a B Klasse as well When you say rough idle, how bad is it Does it smooth out once the engine warms up Have you tried a fuel injector cleaner additive to see if that helps at all before jumping to bigger conclusions It's a simple first step Is the fuel consumption unusually high

It smooths out once the engine is warm It's pretty bad at first, almost like it's misfiring I haven't tried an injector cleaner yet, but that's a good point How effective are those things anyway Also, regarding fuel consumption, it's hard to tell for sure, but it does seem higher than usual Did you end up needing a new injector, or did cleaning work for you

It does sound like it smooths out like mine did I ended up taking mine to a trusted workshop to get a proper injector test done It turned out the injector was indeed faulty Replacing it solved the issue completely An injector cleaning might help in some cases, but for me it wasn't enough I would suggest you visit a professional to avoid further complications

Thanks for the advice I took your suggestion and brought it to a mechanic Turns out you were spot on, a defective injection valve was the culprit Repair cost me around 515€ but now it runs smoothly, even on cold starts