No, the fuellings taken care of by the ECU, so the engine fuels to whatever volume of air is entering it. O.k. it's never going to rival a diesel for economy, but that's not why I bought the car. As for the valve timing, the Duratec doesn't have variable valve timing, so it makes no difference. Ford fitted an IMRC for fuel economy, and low down torque(possibly emissions as well), my car pulls cleanly(if not as briskly) from below 1000rpm in fifth. Anyway the figures speak for themselves, 0-60 in 6.72 secs.