Hi, my van has been slowly losing power at low revs until this weekend it totally lost power at a hill start. Limped up and over hill with foot flat at less than walking pace and black smoke pouring out exhaust. Not been that bad since, but very low on power and leaking diesel somewhere in engine bay when parked (stops after a while). Dripping/running off front crossmember. Coincidentally (?) speedo stopped working recently too (suspect faulty/dirty gearbox sensor?) In neutral, with foot flat it doesn't get past 3000ish and has a muted stuttering sound. Sounds like some kind of starvation? fuel/air? Can hear turbo whistle, so assume it's fine? Please help - need van for work and dealer here is useless! Thanks, mark