The night before last I drove, with a friend, to a meeting about 10 miles away in my recently-purchased Citroen 2008 C5 2.0 HDI 138 Automatic, 61,000 miles on the clock. Three hours later, when I switched on for our return journey, I was dismayed to find that the engine was running extremely roughly - sufficiently to shake the car. No message of any sort appeared on the display, and, having acquired an additional passenger (an elderly lady), I felt obliged to try to get them home, and hoped that whatever the problem was, it would clear itself. No such luck.

After a somewhat harrowing drive, I eventually left the car parked on my drive. Yesterday morning, with some trepidation, I inserted the key again and switched on. To my astonishment, the engine leaped into life as though the previous night had never occurred. Having spoken to my service garage that specialises in European vehicles, I went for a 30 mile round trip, making four stops on the way, without any hint of a problem. And now it has started again this morning. What do you think could have caused the problem, and do you have any suggestions as to how to avoid a recurrence?