2006 Jimny sometimes vibrate in idle

My 2006 Jimny is sometime vibrates in idle, this usually happens in a cold weather, the vibration are not changed if I turn the lights on or off, the car battery is new and it 6000 km after the annual maintenance service.
I have connected the ELM327 scanner and trace the motor behavior during half an hour driving; I noticed that when the car is vibrating the RPM are dropped from ~790 RPM to 650 RPM and the motor load increase from ~25-30% to ~40$ .

I also notice that the O 1X1 sensor is not stable and jumping from 0.2-0.9, this sensor is not stable also during driving.

What should be the behavior of the O 1X1 sensor?
Where can I find the expected values for the other sensor and short description about each sensor role?
What can cause such vibration in the car?

Will appreciate your help,
thanks

Erez

I take it by O 1x1 you mean Oxygen or Lambda sensor from the values you give.

I have never watched the behaviour of one on an oscilloscope, which I assume is how the ELM327 scanner works and I donot have the knowledge to know how to you one to be honest. I try to understand electronics but "try" is the word best described with the success I have in understanding.

My instinct tells me that the values they send to the ECU would not jump about though and may change but not jump.

The Lambda sensor is reading the result of the fuel being burnt, so I can only think that if another sensor is failing, it will effect the mixture of the fuel / air charge and thus what the Lambda sensor reads and then tells the ECU.

However, I shouldn't think it would so much as jump suddenly as much as change relatively quickly as the mixture changes.

The drop in revs causing the vibration is likely caused by the engine running lean.

I would therefore think it is the Lambda sensor it's self due to the jumping of values you describe.

Is the scanner showing values of any other sensors to jump like this or does it not have the capability to watch the behaviour of other sensors? - I am not familiar with it. If it can watch the behaviour of other sensors and none of their values are jumping like this I think it will confirm the Lambda sensor is messing about.

Otherwise - if I am talking complete rubbish - change the Lambda sensor and see what happens.

Kirkynut

Kirkynut,

Thanks for your response.
The ELM327 is a BT scanner that is supported by few software, I am using the free version of torque that runs on Android tablet.

I am able to read all the engine sensors, all of them are stable, the only unstable on is the O 1x1 sensor which is the lambda sensor. the second lambda sensor, O 1x2, is stable.

Do you know which of the two is O 1x1?

Erez