Aygo running rich

Hey there! I had similar symptoms with my Toyota Aygo, though I'm not sure about the year. Have you checked your air filter recently? A clogged filter can definitely mess with your fuel economy. Also, what about the oxygen sensor? A faulty one could be sending incorrect data to the engine's computer, causing it to inject too much fuel. Ever thought about taking a look at the intake manifold?

Thank you for your suggestions. I have not yet checked the oxygen sensor, but I replaced the air filter recently. Can you elaborate on why you think the intake manifold could be the issue?

Well, a leak in the intake manifold could cause unmetered air to enter the engine, which throws off the air-fuel ratio and makes it run rich. Though, honestly, with those symptoms, it does sound like it could be the injectors themselves. Have you considered getting it checked by a workshop? It might save you time and money in the long run, rather than chasing down all these potential issues yourself.

Understood. I appreciate your input. I have taken the car to a workshop. Indeed, the injection valve/injector was defective. The repair cost 515€.