C70 Engine Misfire

Sorry to hear you're having trouble with your C70. A rough engine, check engine light, and jerking acceleration definitely sound like a potential combustion misfire. The 'combustion' part refers to the process of burning fuel in the engine cylinders. A misfire means that for some reason, the fuel isn't burning properly in one or more cylinders. Common culprits include faulty ignition coils, bad spark plugs, or fuel delivery problems. Have you tried checking your spark plugs or ignition coils? Do you notice if the engine is worse when it's cold?

I haven't had a chance to check the spark plugs or ignition coils yet, as I'm not really sure how to do that properly without causing more damage. Could a defective fuel injector also cause these symptoms?

Absolutely, a defective fuel injector could definitely cause those symptoms! A fuel injector's job is to spray a precise amount of fuel into the engine cylinder for combustion. If an injector is clogged or faulty, it can disrupt the fuel-air mixture, leading to misfires, rough running, and reduced power. Given the mileage on your C70 and the symptoms you're describing, it's quite possible that one or more of your injectors are starting to fail. I think it would be a good idea to take your car to a trusted mechanic to have it properly diagnosed. They can perform tests to pinpoint the exact cause of the misfires and recommend the appropriate repairs. Don't ignore it for too long, as persistent misfires can damage your catalytic converter.

Thanks so much for your help! I took it to a mechanic, and they confirmed it was indeed a defective fuel injector, just as you suspected. The repair cost me 515€, but the car is running smoothly again. I really appreciate your guidance!