Hi all, recently bought a silver 175 dci on 108k, in great condition. Had it for just over a week and it has been faultless, but last night I seem to have upset it somehow.

Was having a spirited drive along some country lanes, nothing too harsh but giving it a good boost, went over a hump on the road at speed which caused the front wheels to lift slightly and the ESP kicked in, everything was fine after that, still boosted.

Pulled into a car park a mile or so down the road and noticed it was struggling to drive up the hill, there was no boost. Engine seemed 'lazy' and difficult to rev, but still sounded fine. Parked up, switched it off and left it for a couple of hours.

Came back, started it up, drove home, and the problem remained. I did notice though, that if I plant my foot, eventually the boost does build and it takes off like it normally would, although I have felt some hesitancy a few times.

I've had a proper look over it today, checked the boost pipes to the intercooler and everything seems tight and secure, can't see any splits in pipes although it's difficult to see. Took it down the road and the problem still remains, no smoke from the exhaust, no warning lights on the dash, no untoward noises. I can hear the turbo spooling when I rev the engine.

What on earth could it be?