Ford transit custom 141

For sale Ford transit custom 141, taxed and doe till 11/26 van has always got what it needed always serviced and well looked after, plenty of receipts there for work Glow plugs New clutch and flywheel New wheel hub New alternator New injector Turbo done Brand new DPF fitted 2 years ago Much more stuff done to the van Unfortunately engine management light is on and van is loosing power when it comes up to a hill, have to drop back a gear to climb it any inspection welcome I know nothing about that side of things. Van was minded like a baby unfortunately I don't have the time or money to put into it anymore. Any inspection welcome any test welcome van starts drives great only downfall is when its on a hill it feels like its loosing power