Peugeot 1007 fuel filter heater issue

I had a similar issue with my old Vauxhall Astra, though it was petrol. Error codes pointed to the fuel system, and the symptoms sound familiar. Have you checked the connections to the fuel filter heater itself? How many kilometers?

I've visually inspected the connections, but maybe not thoroughly enough. The car has 126242 km. Could a partially damaged connector cause such a noticeable performance drop, or would it likely be a complete failure?

In my case, it was a partially corroded connector. Enough to throw errors and mess with the fuel mixture, but not a complete break. Given your mileage, corrosion is definitely a possibility. I'd recommend taking it to a workshop. They have the tools to properly test the heater and wiring.

You've confirmed my suspicion about the connectors. I took it to a workshop and it was indeed a corroded connector. The mechanic replaced it and the total repair cost was 95€. Now it runs smoothly again!