Scooter suddenly stops responding to the accelerator, what should I do?

hi guys

My Jetforce (all original, 2-stroke Peugeot engine) doesn't work anymore. I wanted to drive off earlier, and the scooter ran normally, just the usual sputtering from the cold and the echo. Suddenly, it stopped accelerating and stalled, but it idled. I then turned the throttle, but it just misfired (or misfired?) and the rpm barely increased. At some point, it died on its own. But then it started again and later turned off again. Now it won't run at all. The spark plug looked normal (except that it's black and oily… but it always ran "fine"), I don't think that's the problem. It has enough gas and oil in the tanks. My scooter has 12,500 km on it, most of it with a moped throttle. For a few months now, it's been misfiring when the choke was open, and it sputtered when the ignition switch was too old while driving. What could be wrong? I don't want to take it to the workshop right away, but first ask if anyone here has any ideas. Thanks.