Since a year the engine has had serious problems, when slowing down it just shuts down. Specialists hired by Citroen dealers have not been able to solve this, on bad days the car will shut down every time you release the gas before stopping. I have read on a Dutch car magazine web site that it is a known problem with early Xantia's and that it is an engine management problem.
When it works, this is a great comfortable car. The suspension saved our life once (I was able to swerve by a suddenly oncoming fire truck).
I'd the same ignition fault too and this was rectified by replacing the ECU during the warranty period. I guess a replacement chip (IC) would also solve the problem.