Fuel economy gone down ?

[JudgeM]

Hi All,

My Vitz been rather thirsty lately. Just wanted to check if we can pinpoint a reason. I use 91 petrol and injector cleaner every 2500kms

I used to get about 6 liter / 100km now I am getting about 7 liter /100km

First winter with this car for me.

It's winter now, not really that cold like for some of you North guys. In the morning it goes as low as 5c but within a short while its in the 10s. I don't think this would be enough to warrant the increased consumption ?

I have been using the heater alot, does it affect the fuel consumption significantly ?

Also, I think spark plugs haven't been changed for long time. Because they are the iridium dual sharp point type (most expensive type) apparently lasts 100k km. My car has done just under 110k km now. Is it worth changing ? Car starts fine though.

[KCALB SIRAY]

Change your air filter and check your tire pressure. Other than that, you have a 10 yr old vehicle. It would be naive to think it would retain the mpg per factory estimated even after 10 yrs

[2009Toyotoad]

front O2 sensors, they should be replaced at 100K. BTW over kill on injector cleaner, switch to 5k miles not KM. To much stress om the O2 sensor.

[JudgeM]

Change your air filter and check your tire pressure. Other than that, you have a 10 yr old vehicle. It would be naive to think it would retain the mpg per factory estimated even after 10 yrs

Ive had the car for 2 years, was fine last year. Also, before I owned it it has been meticulously serviced. Thats why when I bought it I was okay with it being slightly higher milage because it was in amazing condition.

front O2 sensors, they should be replaced at 100K. BTW over kill on injector cleaner, switch to 5k miles not KM. To much stress om the O2 sensor.

Oh I didn't know about the O2 sensor, I thought it just needs replacement when it dies.
Yea I thought it was abit too much injector cleaner, thats what the bottle said.

[2009Toyotoad]

You might also want to downgrade to 87 octane fuel for a while. Unless you gone with a colder heat range spark plug, you may not be getting all the power out of the 91 octane fuel.

[IllusionX]

You might also want to downgrade to 87 octane fuel for a while. Unless you gone with a colder heat range spark plug, you may not be getting all the power out of the 91 octane fuel.
I believe Australia uses different octane rating, which starts at 91 (RON) which is a 87 PON in North America.


Either way, its winter time, the cooler temperatures makes the car use more gas whether you use the heater or not.
Also, check if you are running on defrost all the time, if you do, the AC compressor is always running to keep moisture low.

[BLKHILLSGUY]

Also keep in mind when you are using the defroster on the front window(2 settings) that is using the air conditioner. Extra fuel. I don't keep mine in the front window defrost mode unless I need to. Kinda hard not to though in winter weather.

[edmscan]

That is not bad at all .... my mileage in the winter goes from about 6 L/100 KM to as high as about 9 L/100 KM. It is definitely weather related .. as my mileage does improve every spring after the weather warms up.

An increase of 1 L like you are getting is really not that unusual.

[JudgeM]

I think its alright. Also we had a warmer couple of weeks just now and it seemed better. Also I have a feeling its the fuel, I am using BP now, was using Mobil.

I never run the AC to defrost.

[bairjo]

Clean the mass air flow sensor. Look how to on you tube.