Megane Reduced Engine Power

Hey, those symptoms sound familiar! I had a similar issue with my old BMW 3 Series. Reduced power, hissing, and rough idle point to a problem in the air intake system. The intake manifold flap controls the airflow into the engine. If it's not working right, it throws off the air-fuel mixture. Has the engine light come on?

Yes, the engine light is on. Is there a way to check the intake manifold flap control? Or is it better to just replace it?

While you could try to check the electrical connections and vacuum lines going to the intake manifold flap control, it's usually best left to a workshop to diagnose properly. These systems can be complex, and without the right tools, you might do more harm than good. A faulty switch will likely require replacement. Expect a few hundred euros for parts and labour.

Thanks for the advice! I took it to the workshop; it was indeed the intake manifold flap control. The repair cost 465€. Runs like new now!