Oxygen sensor

[Spellino]

Originally Posted by 06YarisRS

Did they indicate if it was the upstream (wideband) sensor, or the downstream (post-cat) sensor? The upstream sensor measures air/fuel ratio, the downstream sensor measures residual oxygen after the exhaust has passed through the cataylic converter. Upstream sensor = more expensive, can effect driveability, fuel economy, downstream sensor = less expensive, should have no effect on driveability. It is an easy DIY job but finicky. The hardest part I found was getting up into the car and unclipping the connectors. I bought a very cheap (~$17.00) downstream sensor, but wouldn't have cheaped out on the upstream if I had had to replace it.

No. I was just told it's the oxygen sensor and that he wouldn't recommend that I change, due to the fact That in my country, Ghana, it will be difficult to buy unleaded fuel and changing it will fix it temporarily.

He opened the hood to show me where it was, just behind the engine.

I'm beginning to think I should take the car somewhere else. Are you saying that there are two? Mine is the 4 speed automatic