Our nearly three year old, new to us C4 went into 'limp mode' today, citing a pollution filter fault or something. The car decclerated suddenly and only went back to normal After I turned off the engine and restarted. It's been fine since. Looking at forums it seems this is a 'feature' of Citroens. It seems really dangerous that a huge range of often trivial faults can cause the car to sudddenly slow down with no warning. What if you were overtaking? Does anyone have a Citroen and experienced a similar problem? And can this 'feature' be disabled? Even if the garage fixes the problem, which seems unlike from what other owners are saying, how can I ever feel confident that it won't sudden;t happen again? I dread to think what would happen if the car sitting on my tail had crashed into me, or worse, if it had been a big lorry.