In May, following a major loss of power, my Ford dealer diagnosed low fuel pressure & replaced the fuel filter. The problem occurred again in July & they replaced the turbo. This week the engine malfunction warning light appeared with another reduction in power. Now the dealer says I need a new DPF & sensor. Might the DPF/sensor have been the problem all along & I didn't need a new turbo? Is this the type of problem that's difficult to accurately diagnose, or could all these different parts have become separately faulty in a short space of time, or might the garage not be doing a very good job? Once this problem occurs in this model is it likely to keep recurring, or is it fixable? Mileage 100,000.