For a while now I have had the impression that the amount of available power from the engine was gradually tailing off especially when you needed it most (when overtaking). Because the decay was gradual it wasn't immediately apparent and not bad enough to warrant a full investigation. However, I was travelling up the A9 last week when I tried to overtake a couple of times. I lightly pressed on the throttle as usual without changing down a gear (a very nice feature of torque availability), pulled out into the oncoming lane and failed to accelerate. This was very disconcerting. It required a panic shift down a gear and foot flat to the boards.
Aftr I regained my composure I began to think of the possible causes. It had all the symptoms of Turbo failure but without the accompanying noises. I pulled into the next lay-by and popped the bonnet. After a bit of fishing around with the engine running I could feel a jet of air coming out of the rubber hose connecting the intercooler to the intake manifold. I took it off to reveal a split in the hose at the back out of sight. The turbo was pumping fine but the air was escaping before it reached the intake manifold.

I temporarily bound the hose with duck tape. It will probably remain the solution until I can pluck up the courage to ask for a price from my local Citroen dealer. It's unlikely to be manufactured by anyone other than Citroen although I'm all ears if someone knows differently.

cheers

noz