Passat 1.8GSI problem

There is a great possibility that the throttle is broken, and it is not necessarily that people are fooling you. Pay in good condition, pay in bad condition. If you really want to confirm it yourself, contact a friend who is the same as your car and flip it from his car to yours to try the effect. It could be a wire harness. Of course, checking these things is not something you can do alone, and it costs money.