In March 2020 we were on our way back from a vacation trip, when suddenly upon an uphill acceleration a short but pretty loud rattle came from the engine. The same moment, all power was lost, "Antipollution error" popped up and the engine malfunction light went on with an annoying beep from the instrument cluster. Pulled over on the hard shoulder and tried to start. The starter did crank, strangely enough much faster than normal. But the engine did not fire up. It seemed there was no (or hardly any) compression so I was convinced that the worst had happened: broken timing belt (which had just been replaced btw) or some broken valve or whatever. I decided to leave it like that and had it towed away.
The car was transported back home at insurance cost. At home we lifted the rocker cover. I expected to see a terrible mess; however, all was perfectly fine. No broken metal bits, no loose parts. So we turned the engine by hand, and found all four cylinders having compression. In the end we decided to give it a go and, yes, it fired up perfectly! No ratting sound, no smoke, it ran perfectly normal.
About 1 year later a similar event happened. Heavily loaded (six persons + luggage), it was the first heavy hill climb after a year of all flat and slow driving (in NL the maximum speed is 100 km/h and there are no hills). The rattle starts unannounced, very subtly, but then increases within a few seconds to become pretty loud. This time it happened during the day so I could see an enormous blast of grey smoke in the rear view mirror. Loss of power, pulled over, but the engine kept on running in idle. So after a few minutes of recovering from our shock, we resumed the trip. No further problems.
A week ago again, on another vacation trip. Heavily loaded, first steep and long hill climb after a year of duff driving. Loud rattle, heavy smoke (definitely gray, not blue or black or white), "Antipollution error", EML light with a beep, complete loss of power (and wife in total panic).
Pulled over, engine had cut off. Tried to start. Again the cranking was much faster than normal, but the engine did not fire up. After bringing all the kids to safety behind the guardrail I decided to give it another go and yes, it started! So we all got in again and drove to destination without any further issues. EML light was still on but engine was running smooth as ever, no smoke, no loss of power (not even limp mode).
At arrival the EML light was still on. As an experienced PSA driver, I have my Lexia cable with me (never leave home without one

But P1112 is new for me. It seems the high pressure fuel pump could not generate enough pressure when the failure happened. It says 769 bars at 97% duty cycle. I guess the pressure should be much more (was at full throttle when the failure happened).
The next day the EML light no longer lit up, everything was normal again (and still is).
I am flabbergasted why a perfectly running engine suddenly dies with a loud rattle and loads of smoke, seems to loose compression, then starts again perfectly after a few minutes!
Bear with me: I have to explain my wife I want to keep a motor that runs perfectly fine for a whole year, bringing me to work every day, then fails horribly, without any warning or signs, when driving to a holiday destination.