Ask the Mechanic: How can I improve my car’s fuel consumption?

I have owned a used Toyota Probox 1300cc for a year. Its fuel consumption was 8.5 km/litre but after removing the exhaust muffler, it is now doing 12.5 km/litre. We changed the spark plugs but there is no difference despite the engine’s good condition. What should be the consumption of a 1300cc engine?


Hello Mukisa, the declared fuel economy statistics for the 1300cc Toyota Probox are 13-19km/litre. This means your 12.5 km/litre is close to the lower limit of that expected range. There are reasons, besides engine tuning, why you are not achieving the peak fuel efficiency of 19km/litre. Look into the factors that affect fuel efficiency such as tyre condition. Also, worn out or wrongly inflated tyres require more engine power (energy loss) to run.

Your driving style, aggressive acceleration and jack rabbit stops also reduce fuel efficiency. Where you are driving also matters. Cars consume more fuel when driving in start, stop, slow city traffic because you are restricted to lower gears which are energy sapping, while highway driving allows you to shift to higher gears which reduce energy (fuel) demand on your engine. Highway driving gives you better fuel efficiency as long as you do not speed and keep the small engine in the energy sapping high rev curves.

The amount of cargo you are carrying also adds to the energy demand on the small engine. If the Probox is overloaded, then the small engine will operate in the high rev curves.

The choice of recommended engine oil quality (fully synthetic 5W30) and cleaner, more efficient fuel, matters for the Probox’s 1NR FE or 2NZ FE 1300cc engines, which are designed with fuel efficiency enhancing but oil and fuel quality sensitive technology such as dual VVTi, multi-point fuel injection, chain drive and euro 4 emission system.

What is causing


My 2009 Toyota Belta runs smoothly but makes a whizzing sound when I accelerate. My mechanic thinks I should replace the gearbox pump but he has been wrong before on another issue so Iam hesitant to follow his advice. What do you think?


Hello Geoffrey, fixing cars is like treating patients. Sometimes, your mechanic can get it wrong. This does not mean you should write them off. There must be a good reason why he thinks the noise is caused by the gearbox pump.

Keep his diagnosis in mind and compare with a second opinion before making the repair decision.

Without inspecting the car or listening to it myself, it would be unfair to dismiss the opinion of someone who has had contact with the car.

However, without inspecting the car, I will say that any noise in the transmission during acceleration is a sign of mechanical or hydraulic system failure, which should be inspected to determine what is faulty.

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