Mercedes ML Diesel Cylinder Pressure Issue Resolved

Cylinder pressure fluctuations can indeed stem from fuel injector issues. Have you considered assessing the injector spray pattern? A leak-down test might also offer insights. Though less frequent at your vehicle's mileage, worn piston rings can contribute. The crankshaft position sensor should also be checked. Is the engine misfiring?

Thanks for the quick reply. I haven't checked the injector spray pattern directly, no. Is that something easily done at home, or does it require specialized equipment? Also, if the crankshaft position sensor was faulty, wouldn't I expect more consistent misfires, rather than just these fluctuations?

Injector spray pattern assessment generally requires specialized equipment for accurate diagnosis. Regarding the crankshaft position sensor: you are correct; consistent misfires are more typical. However, intermittent signal disruptions can also occur. Given the potential complexity and consequential error you’re experiencing, a professional diagnostic assessment is advisable. It might save you time and money in the long run.

Appreciate the advice. I took it to a workshop, and it turned out to be a faulty sensor causing all the issues. It was throwing off the fuel mixture and causing the cylinder pressure variations. The repair cost was 0€, covered by an extended warranty!