GLC Hybrid Engine Misfiring Issue

I have a GLC too and had a similar experience: rough idle, check engine light flashing, occasional jerking when accelerating. Engine misfiring can come from a few things. Have you checked the ignition coils? A bad coil can cause incomplete combustion, leading to misfires. Also, think about the fuel pump. Not enough fuel can also cause misfires, especially at higher RPMs. What diagnostic codes are you getting from the check engine light?

I appreciate the insight. Ignition coils seem fine, resistance is within spec. Fuel pump seems okay, but I haven't done a proper pressure test. The code I'm getting is P0300 Random Multiple Cylinder Misfire. Any thoughts?

P0300 is a vague code. Since the ignition coils seem okay, and you suspect the fuel pump, the next most likely thing, in my experience, is a bad fuel injector. Fuel injectors spray a precise amount of fuel into the cylinders. If one is clogged or not working right, it can cause a lean condition, leading to misfires. A lean condition means there isn't enough fuel in the air-fuel mix for proper combustion. Given your symptoms, I'd suggest having the injectors looked at. I'd advise you to visit a trusted workshop.

Thanks for the suggestion! It was a defective fuel injector. I replaced it, and the engine runs smoothly again. Total cost was 515€ for the injector and labor.