Peugeot 307 excessive smoke exhaust

I think you are on the right track. I remember there were some issues with the pressure sensor on that model. The symptoms you describe are extremely similar. Have you had any diagnostics done to confirm the error?

Thank you for your prompt response! No, I haven't performed any diagnostics yet. I was hoping to gather some insights from the community before taking it to a mechanic. Could you perhaps elaborate on the diagnostics you're referring to? Is it something I can do myself, or would you recommend visiting a workshop?

Given the symptoms and your initial assessment, it's probably the exhaust back pressure sensor. While basic OBD2 readers exist, interpreting the data for something like this can be tricky. Your best bet is a workshop; they have the right tools and expertise for accurate vehicle diagnostics.

I sincerely appreciate your advice! Based on what you've said, I'll schedule an appointment with a trusted workshop to get a thorough assessment. It turned out that the exhaust back pressure sensor was indeed defective and the repair cost me 245€. Thank you for pointing me in the right direction!