Engine management fault led to replacement of catalytic converters (all 3 of them) and lambda sensors, fortunately under warranty.
Engine speed sensor replaced.
Engine earth connection replaced.
Ignition coil failed, all 6 replaced.
Poor BSI connector repaired (multiplex wiring controller), led to various apparent faults and difficulty in diagnosing them as its the interface for the diagnostics.
Repeated (4 or 5) updates of software and fuel/timing maps over last 6 months have failed to resolve performance problems until latest download. Loss of power, delayed throttle response, erratic throttle response and gear changes (auto) combined to make the car's response to accelerator movements unpredictable.
An engine vibration coupled with uneven running in low rev range was introduced by a software update and still not cured although now much reduced.
It seems Peugeot's techs just can't get it quite right however many times they try.
Thank God its under warranty.
Every time it needs a spare part its off the road for days because they are never in stock at dealer or Coventry, or often even in France.
The parcel shelf and its mountings rattle and creak continually. I fixed one side after 3 attempts with self adhesive foam padding. My 2 previous 406 estates had same problem.