Weekend JTD poor on hills

:bang: I note that many people seem to suffer from poor running in low revs and lack of power. I have had the timing checked, a new mass meter but still the car lacks power on hills or when travelling slowly, it is necessary to slip the clutch. Putting one's foot on the accelerator and nothing happens. When the Turbo kicks in it is fine. Surely with so many suffering from the same problem Fiat should know what is causing the problem?