Customer changed timing chain and then vehicle developed lack of power. Fault code PO170 stored (fuel trim). Emissions (4 Gas) excellent at normal and fast idle. Vacuum good at normal and fast idle. Ticks over ok. However customer went for MAF and swopped for S/H unit. Also changed cam, crank and 02 sensor.What I have found is MAF only goes up to 3V which I think is a consequence of the fault. When revving engine, butterfly is only partially open at about 5K revs. Accelerator pedal sensors read ok, but both TPS's are significantly under reading. When actuating throttle butterfly via acr 4, it snaps wide open. Vehicle will apparently reach 70mph after an age. Suspect throttle motor or ecu fault. Not done fuel pressure check - yet. Good these fly by wire cars! Any ideas? Many thanks