Hello everyone, first post 
My Armada is an '06 with 76,000 miles. I haven't had hardly any problems with it until the past couple of weeks. First sign of trouble was when my wife was out and said the SES light came on and it seemed to be idling rough. About 20 minutes later she was almost home and said it had almost no power and was barely making it up the hill to our house. I got home shortly after and checked the code using OBD Fusion app on my iPhone. Was still idling super rough and showing code P0300 Multiple Cylinder Misfire.
Car sat until the next day when I started it up again to see if there was anything else I could tell from it. When I started it, the code was gone and she was running perfectly. Hallelujah! I took it out for a quick drive and everything was great. I got back home and pulled it into the driveway and let it sit and idle for a bit. Within about two minutes the idle started to get a little rough and the SES light came back on with the same code.
A couple days later I decided to try to start it up one more time and look at some of the other info on the OBD fusion app. It doesn't have a whole lot of monitoring data to display, but it does show the O2 sensor readings so I decided to watch those in real time. It lists O2 sensor 1 and O2 sensor 2 on the app. I am assuming that this is referring to the downstream O2 sensors and not the Air/Fuel ratio sensors in the exhaust manifolds. I am also assuming that it means Bank 1 O2 sensor and Bank 2 sensor (does anyone have any experience with OBD Fusion that could confirm this?). Anyway, I started it up again and (again) she started right up and was running great. This time I went out and drove it for about 20 minutes with no issues at all, idle at stop lights and stop signs was still great. Got back home and pulled it in the garage and within about 5 minutes, guess what, started to idle rough and code came back. Idle would be rough and then sometimes briefly would go back to normal. Watching the O2 sensors readings showed something interesting. O2 sensor 2's voltage readings were pretty consistent. O2 sensor 1, however, when idling rough and with the P0300 code active would be bouncing between 0 volts and 1 volt. When the engine would return to normal idle/code gone, O2 sensor 1 would be reading around .3 volts. I don't know if this is an indication that the O2 sensor is going bad or if it is the O2 sensor's reaction to whatever the actual issue is.
I know that was alot of information, but wanted to give as much as possible so maybe someone might have had a similar situation to share. All help is greatly appreciated.
My Armada is an '06 with 76,000 miles. I haven't had hardly any problems with it until the past couple of weeks. First sign of trouble was when my wife was out and said the SES light came on and it seemed to be idling rough. About 20 minutes later she was almost home and said it had almost no power and was barely making it up the hill to our house. I got home shortly after and checked the code using OBD Fusion app on my iPhone. Was still idling super rough and showing code P0300 Multiple Cylinder Misfire. Car sat until the next day when I started it up again to see if there was anything else I could tell from it. When I started it, the code was gone and she was running perfectly. Hallelujah! I took it out for a quick drive and everything was great. I got back home and pulled it into the driveway and let it sit and idle for a bit. Within about two minutes the idle started to get a little rough and the SES light came back on with the same code.
A couple days later I decided to try to start it up one more time and look at some of the other info on the OBD fusion app. It doesn't have a whole lot of monitoring data to display, but it does show the O2 sensor readings so I decided to watch those in real time. It lists O2 sensor 1 and O2 sensor 2 on the app. I am assuming that this is referring to the downstream O2 sensors and not the Air/Fuel ratio sensors in the exhaust manifolds. I am also assuming that it means Bank 1 O2 sensor and Bank 2 sensor (does anyone have any experience with OBD Fusion that could confirm this?). Anyway, I started it up again and (again) she started right up and was running great. This time I went out and drove it for about 20 minutes with no issues at all, idle at stop lights and stop signs was still great. Got back home and pulled it in the garage and within about 5 minutes, guess what, started to idle rough and code came back. Idle would be rough and then sometimes briefly would go back to normal. Watching the O2 sensors readings showed something interesting. O2 sensor 2's voltage readings were pretty consistent. O2 sensor 1, however, when idling rough and with the P0300 code active would be bouncing between 0 volts and 1 volt. When the engine would return to normal idle/code gone, O2 sensor 1 would be reading around .3 volts. I don't know if this is an indication that the O2 sensor is going bad or if it is the O2 sensor's reaction to whatever the actual issue is.
I know that was alot of information, but wanted to give as much as possible so maybe someone might have had a similar situation to share. All help is greatly appreciated.
