Looks like I have a o2 sensor out time to change it... I had to order the sensor should take a couple of days. Is it okay to drive with the bad sensor, I can not see how it would hurt anything? I am not going on any long drives just store back.

Thanks,

J

 

What was your exact fault code and what is the truck doing? At you mileage, I would suggest you replace all 4 so you can keep your air/fuel ration at it's best setting for more power and mileage.

 

Driving with dead sensors is fine for a little while but your truck will default to running rich so you will get even worse gas mileage.

 

Thanks for the reply, it running great I am pretty sure it has something to do with, I changed the seal from the output shaft seal on the transfer case a week ago. I drove it about 400 miles then the check engine light came on. The code it is giving me is P0159 o2 slow response. Besides the light it is running great.

 

HI , i have a 03 disco with 80,000 miles. i do i know if an 02 sensor goes bad? does any lights come on?

 

You will get a code thrown and the check engine light will come on.

 

Resurrecting this old thread

I recently had my valve cover gasket spring a leak and I replaced it.
Oil had been leaking down to both of the O2 sensors, one a bit worse than the other.
I also changed my oil from Rotella Synthetic T6 to Rotella 15-40 (Mobile 301 extended filter) while I did the valve cover gasket.

So... Ever since, my gas mileage has plummeted, drastically.
I'm averaging 10mpg.

However, I have no codes and no CEL.
Is it possible the front O2 sensors are causing this due to the oil that leaked down their cables and coated them?

I have 2 front O2 sensors coming tomorrow to install because I have nothing else obvious to act on.

As a side note, my engine tick came back in a big way after changing from the synthetic to the dino 15-40

Thanks guys.

 

I'll answer my own question.
Yes, without a doubt O2 sensors can be bad without throwing a code. In my case, the truck seemed to be running fine other than the **** poor gas mileage. I replaced the front 2 and one of them was badly fouled up. All good now, back to regular gas consumption. I used Bosch from Amazon.