[cole92ton]

I've been having codes related to my primary bank 2 O2 sensor for a little bit now, but only recently has it become an issue.

My car began having a cylinder 5 misfire, so I changed the OEM Bosch spark plugs with NGK 95770's gapped to .022.

I've had them in the car since yesterday, no more misfire but the car still is acting finicky, as the car starts very roughly when warm and there is a very potent smell of unburned fuel from the exhaust.

The car has been running rich lately, as I've noticed lots of carbon and soot build up on the exhaust tips and my rear bumper as well as that smell of unburned fuel. So, I figured it must be the O2 sensor. However, after taking out the O2 sensor and cleaning it off (I soaked it in gasoline and lightly used a shop towel to take off the carbon build up that was covering the sensor, which I believe to be the issue). The car is no longer reporting the Lambda Control 2 code which it was prior to cleaning the sensor, however, like I said it is still running rich.

Does changing this sensor seem to be the most obvious fix? Or could it be something else, like a stuck open injector? I've already ordered the part, I'm just skeptical to replace it and not fix the issue since I'm tight on money at the moment. Sorry for the rather long post, just wanted to give as much context as possible. Any advice is appreciated, thanks!

[domain007]

Sorry to say this but a misfire on cold start usually indicate bad injectors i just replaced all 6 of mine and had cold start misfires and O2 related codes. if you have a crappy injector i would change them asap as the excess fuel can drip past your rings and ruin your oil (cause a spun bearing) and kill your cats .. dont ask how i know :'(

[cole92ton]

Originally Posted by domain007

Sorry to say this but a misfire on cold start usually indicate bad injectors i just replaced all 6 of mine and had cold start misfires and O2 related codes. if you have a crappy injector i would change them asap as the excess fuel can drip past your rings and ruin your oil (cause a spun bearing) and kill your cats .. dont ask how i know :'(

Thanks for the response man, much appreicated. However, I was only getting a misfire in cylinder 5 because after removing the OEM spark plug, it looked like crap compared to the rest of the cylinders. I'm not sure why but it was covered in carbon soot and looked as if the prongs were almost bent. I changed the plugs as I mentioned and the misfire has not returned. This is why I believe the O2 sensor should (hopefully) fix the issue.