Car: Peugeot 207 2007, 1.4 HDI engine 8HZ 1398cmc, 50kW
Symptoms: everything (cold/warm start, idle, accelerating with no load/some load, etc) works as expected, except that sometimes there's an abrupt and very short (like half a second) jolt from, what I assume, is some sort of loss of power. I would describe it as if the fuel was cutoff for a very short amount of time and then recovers instantly, but I have no idea if that's what really happens.
When does it happen? I really cannot find a pattern, as it happened in all sorts of conditions, but it seems to happen more frequently when driven at higher revs and on terrain which isn't flat.
What I've tried:
- taken to a mechanic: they said to come back when it's reproducible, as there's no faults and they couldn't trigger it on a short drive
- changed the intake air temperature (IAT) sensor: I've used an OBD logger to try and find anything strange, and I found it strange that the IAT sensor reports temperatures between ambient and 130°C and also some black debris on parts of it -- so I've replaced it, but that didn't help
- more expensive fuel
- italian tune-up
view under the hood:
old IAT sensor with some black debris:
FLIR confirming the high IAT temps:
Thank you for reading and any ideas/leads very much appreciated 🙏