I'm adding this thread purely as help to anyone who owns a Peugeot 206 which has or is behaving in, what can only be described as, a dangerous manner.
Our case begun about 6 months ago where, for no apparent reason, our 206 started to inexplicably lose power whilst travelling at speed, then immediatley pick up again, causing a jerking motion. Sometimes it wouldn't pick up again at all and grind to a halt. This was particularly dangerous when happening in the fast lane of a motorway. Other problems would include massive over revving whilst at a standstill, general stalling and jerking in slow moving traffic. Driving became very stressful (not to mention a bit of a lottery as to whether you made it home in one piece).
The thing is that when it was taken in to the dealer, they hooked it up to the computer which would show absolutely no fault at all, leading to a speculative diagnosis on each visit which invariably cost money (since the car was way out of warranty) for parts changed, which turned out to be unecessary.
To cut a long story short, our car gave out a crack on the way home from work one night, and the following mornign wouldn't start. It turned out that the coil pack had blown and spiked the ecu (the engines central computer). We had it towed to an alternative Peugeot dealer who's service manager told us it would cost about £1100 to fix. He seemed aware of this problem and agreed to fit a non Peugeot ecu if we bought one (for about half the price), which we did and all was and is now well.
Peugeot as a manufacturer still deny to this day that there is an inherent problem with their ecu's and this has lead to an online petition for 206 owners to lsit their cases - the results of which can be seen here -
Peugeot 206 Online Petition
If you know of anyone with this problem or you've suffered yourself, take the time, as I did, to add your case to the growing list. Looking at some people's cases, it's only a matter of time before someone's killed.