I'm not saying that this is the reason your Mercedes is misfiring I'm simply offering my opinion based on experience. The ecu controls the injector pulse, cylinders and all the sensors. So if your Benz misfiring make sure you rule out the ecu 1st. If the ecu is the culprit then here is some good information on how to test it and remove it. How to remove a Mercedes C240 ECU control unit

Good luck with it