Peugeot 408 Hybrid Fuel Delivery Issue

I read your post with interest, as I also own a 408 and have experienced similar symptoms. The convergence of poor starting, elevated fuel consumption, diminished power, and unstable idling does indeed suggest a fuel delivery anomaly, as you surmised. Out of curiosity, have you observed any unusual exhaust emissions or atypical engine noises in conjunction with these symptoms? Has the engine management system illuminated any warning indicators?

I haven't observed atypical exhaust emissions or unusual engine noises beyond the uneven idling. However, the engine management system has illuminated the malfunction indicator lamp (MIL) several times. Diagnostic scanning revealed a fault code for a fuel injection system malfunction, without pinpointing the specific nozzle. Have you replaced the nozzle yourself? Which brand did you buy?

Given the illumination of the malfunction indicator lamp and the fault code for the fuel injection system, it seems your assessment of a defective injection nozzle is accurate. I brought my car to a workshop to ensure all 4 nozzles were clean and the gasoline circuit was in good condition. I advise you to consider a similar course of action, as replacing or servicing fuel injection components requires specialized tools and expertise to ensure proper calibration and functionality.

I appreciate your advice. I've decided to take the vehicle to a reputable workshop for diagnosis and repair. The estimated cost for replacing the defective injector and recalibrating the system is about 515€.