Question 1: Sometimes, the gradient of the road and the speed of the traffic combine such that I have to choose between two consecutive gears, neither of which are perfectly suitable for maintaining the speed. For example, if I use 3rd gear, the engine runs fine but it revs a little too much (I like to keep it under 2100rpm if possible), but if I shift up to 4th gear the engine will practically lose its ability to accelerate (flooring the throttle only causes no discernible acceleration but the speedometer needle will creep upwards slowly), and the engine makes a compressor-like noise (phut phut phut) rather than the normal vroooom sound.
The question is this: which one of the two situations above will be most fuel-efficient in a 1.4 litre petrol engined car? Sure higher gears are meant to be better, but does the engine lose efficiency if it's being lugged?
Question 2: Also, I normally shift up at 2000 rpm (I normally keep engine RPM at 1500 and average speed is normally 60km/hr). Also I coast when I can and don't really use engine braking (in that I slow the car down using the brakes, then press the clutch when the engine is close to 900 RPM; I don't bother shifting down through the gears to slow it down, I just use my brakes) yet my car consumes 10 litres per hundred kilometers on average (measured accurately based on how many litres I put in the tank and how many kilometers I travel until the fuel indicator returns to its original position). Anything I'm doing wrong to get such high fuel consumption? The car is a European Ford Fusion with 1.4 litre duratec petrol engine, 5 years old and has about 3mm extra engine oil (when cold) according to the dipstick.
The question is this: which one of the two situations above will be most fuel-efficient in a 1.4 litre petrol engined car? Sure higher gears are meant to be better, but does the engine lose efficiency if it's being lugged?
Question 2: Also, I normally shift up at 2000 rpm (I normally keep engine RPM at 1500 and average speed is normally 60km/hr). Also I coast when I can and don't really use engine braking (in that I slow the car down using the brakes, then press the clutch when the engine is close to 900 RPM; I don't bother shifting down through the gears to slow it down, I just use my brakes) yet my car consumes 10 litres per hundred kilometers on average (measured accurately based on how many litres I put in the tank and how many kilometers I travel until the fuel indicator returns to its original position). Anything I'm doing wrong to get such high fuel consumption? The car is a European Ford Fusion with 1.4 litre duratec petrol engine, 5 years old and has about 3mm extra engine oil (when cold) according to the dipstick.