Fuel Economy Decreasing

[sacpul]

Hi Guys

My 4WD Vitz normally makes between 25 to 30 mpg. These last days is not economical as it was. The mpg is decreasing.

The plugs has been changed about 2000km ago and the cone filter has been cleaned. The Maf has been cleaned too.

What are the other parts that i need to check? The car speed and bhp is normally as it was. Nothing has changed but only the MPG and also my wallet to pump more fuel in the tank. :)

Best Regards

Sacpul

[cmarshall]

Hi, i dont know what the weather has been in your area but over here the temperature here has decreased a fair bit which always lowers fuel economy

[Karma Supra]

Lambda sensor!!!!

[Gnome]

Engine oil and oil filter?

When were they last changed?

They'll help a bit.

[sacpul]

Engine oil and oil filter?

When were they last changed?

They'll help a bit.

←

They has been changed with the plugs. I service the regularly @ 4000km changed oil and oil filter and about 10,000 to 15,000km change the plugs.

[sacpul]

Lambda sensor!!!!

←

What is the Lambda sensor? and where is found in the car?

[jay dh]

didnt know a 4x4 vitz existed

[sacpul]

didnt know a 4x4 vitz existed

←

available only the japan version name vitz. the european version yaris does not have the 4wd version. there more models in 4wd but only the japan version.

[Karma Supra]

The sensor will be somewhere on the downpipe I would assume... essentially it reads the exhaust gasses so the ECU can analyse them and adjust the fueling accordingly...

MY stem seals are shot on my car, the resultant oil smoke every time I started it has covered my lambda sensor, my fuel economy has gone down from 400 miles a tank to about 280....... but there is no point in changing the sensor untill I have changed the seals.... ho hum....

[IceHz]

also make sure the tire pressure is correct... can have quite an impact on fuel economy. recommended is 33 PSI front & 30 PSI rear.

Cheers!

PS: Its nice to know you have already checked out the basic stuff.

[mabean]

I noticed my MPG was falling a bit, got service and it's jumped back up about 4/5 mpg!!!

:)