I've got a TW wagon, 178,000k's, regularly serviced etc. Last month or two the fuel economy has been getting staedily worse, no matter how hard i try to drive smoothly or with a light foot. Average fuel economy has gone from 9.8-10 L/100km to 11.5L/100km (i live in a rural area, not city commute). I use only 98 fuel no ethanol. No obvious leaks etc.

I'm thinking that the oxygen sensor is playing up, any other ideas? How to check the sensor? and how much to replace?

I've got a TW wagon, 178,000k's, regularly serviced etc. Last month or two the fuel economy has been getting staedily worse, no matter how hard i try to drive smoothly or with a light foot. Average fuel economy has gone from 9.8-10 L/100km to 11.5L/100km (i live in a rural area, not city commute). I use only 98 fuel no ethanol. No obvious leaks etc.

I'm thinking that the oxygen sensor is playing up, any other ideas? How to check the sensor? and how much to replace?
im getting 13.1 soft driving but then again im in the AWD TW VR-X

I dare say it s the oxygen sensor, especially if it is still the original.

Thanks guys, i'll book it in for a service and get sensor checked/changed

Could be the lead in your right foot too..

Happens to me from time to time..

SuFz :ninja:

Thanks guys, i'll book it in for a service and get sensor checked/changed

Just be wary of the price you get charged. OEM part + labour could end up a considerable cost when compared to doing it yourself.

im getting 13.1 soft driving but then again im in the AWD TW VR-X
Just had my battery die on me, but I was previously sitting on 19.1L/100kms after close to 4k kms.

Just had my battery die on me, but I was previously sitting on 19.1L/100kms after close to 4k kms.

Wow that's a lot! Oxygen sensor for sure. If it isn't, it's probably due to be replaced anyway, and certainly wouldn't hurt replacing if it's up in mileage.

Hope you put a decent enough battery in, and not one of those imported products...

Wow that's a lot! Oxygen sensor for sure. If it isn't, it's probably due to be replaced anyway, and certainly wouldn't hurt replacing if it's up in mileage.
It's just hit 112xxx ks!! I'm also still on my L's, don't want to think what it will be once I get my P's.... I thought this was a fair enough figure for a 3.5l v6 AWD?

oxy sensor for sure or a dirty AFM

It's just hit 112xxx ks!! I'm also still on my L's, don't want to think what it will be once I get my P's.... I thought this was a fair enough figure for a 3.5l v6 AWD?

Around town using Shell E10 I average low 14s, on the highway 9.5-10.5 depending on circumstances.

Around 160000km would be the expected life of an oxygen sensor, but they occasionally fail earlier.

128k - around town currently 11/100km (down from 11.7 since changing air filter!) havent done long trip in it yet but hoping for close to 9.0?

It's just hit 112xxx ks!! I'm also still on my L's, don't want to think what it will be once I get my P's.... I thought this was a fair enough figure for a 3.5l v6 AWD?

BTW, if the engine is running well and the oxygen sensor is okay, you might want to get the coolant temperature sensor and its wiring checked out. If the ECU thinks the engine is cold it will be running it rich in warmup mode. The easiest way to check this is if you can find someone with an Evoscan setup which can log the coolant temp (when warmed up, the logged value would normally be around 95-100C in my experience).

Yours is the second AWD I've seen reported on these forums to be routinely consuming around 20l/100km for no apparent reason. AFAIK, the reason for the other car's excessive consumption was never identified (beyond accusations lead footedness).