Why do I get such poor petrol consumption and what should I expect

A NON USA CAR, where is it what country? (engines and EFI vary by, countries sold to) (2 engines in 2001) near same but....what/?
1.3 L M13A I4 (petrol) with VVT
1.5 L M15A I4 (petrol) with VVT (VVT can fail and lose power too)


well, you did not do the right tests.
not using a scan tool first is #1 cause of going astray, do that first.
Fuel consumption low tell me it, the ECU is in limp mode. and the ECU has lots of DTC errors you are ignoring.
low power has many causes. not just one #10 filter. inside the tank
let me list them to you , in no order, and is ASE class 101 basics, all the way,

1. low fuel pressure, bad filter,bad pump bad FPR fuel pressure regulator. we use a hand tool gage to find that.
2. bad MAF sensor has this, NO ENGINE STATED BY YOU!
3. bad spark if misfiring, ever do a tune up in 60,000 miles.????
4. Bad fuel ,
5. clogged or leaking fuel injectors.
6. bad engine, is compression at spec? (more tools)
7. CAT Melted, (ignoring those DTC error caused this)

that is about it, can go more, but you have no tools to test, so find a shop , to fix this car, as they SURE DO HAVE all tools to do that job right and fast.

If it is black smoke the engine is running too rich. There is too much fuel being sent to the cylinders so it doesn't burn the fuel cleanly. You'll get poor fuel consumption. Check the smoke doesn't have a blue tint to it as that is caused by burning oil.

best at 10 liters per 100 klms , average around 12 liters /100 klms
fuel consumption depends largely on load , speed , operating conditions , towing, highway/city, off road so an exacting answer is not possible as it all depends on the operator and the driving skills

http://www3.toyota.com.au/prado/specifications/kakadu-petrol-auto

This is a link with the most current info on the Prado straight from Toyota.

The Nissan X-Trail was distributed to Australia through Nissan Australia. The fuel consumption figures for the different engines are below.
Petrol: 9.1L/100km
Diesel: 7.4L/100km

change the plugs and the air filter &try not to speed, that always consomes more fuel. if that dont help, change the plug wires

Unless you have an engine light on, the first thing I would check is tire pressure. You should run at least 35 psi. Tire size can make a big difference also, smaller is better. If you have very large off-road tires, you will pay for poor rolling resistance. Use skinny, tall tires for better mileage. The other obvious item would be the air filter, make sure it is new every 10,000 miles. The computer is programmed to deliver fuel for an expected amount of air delivery, if the air can't get through, it will run rich and get poor mileage and performance.

check air mass.

I would not really recommend buying a petrol engined Isuzu if you are thinking about fuel consumption.I think you will be lucky to get 8km/l and thats being generous.Rather go for a turbo diesel with around the same capacity and you should get between 12-14km/L.